1211126550 has 96 divisors (see below), whose sum is σ = 3151084032. Its totient is φ = 307486080.

The previous prime is 1211126549. The next prime is 1211126551. The reversal of 1211126550 is 556211121.

It is an interprime number because it is at equal distance from previous prime (1211126549) and next prime (1211126551).

It is a super-2 number, since 2×1211126550² = 2933655040229805000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1211126550.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211126551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 258529 + ... + 263171.

It is an arithmetic number, because the mean of its divisors is an integer number (32823792).

Almost surely, 2^1211126550 is an apocalyptic number.

1211126550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211126550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1575542016).

1211126550 is an abundant number, since it is smaller than the sum of its proper divisors (1939957482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211126550 is a wasteful number, since it uses less digits than its factorization.

1211126550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4742 (or 4737 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 24.

The square root of 1211126550 is about 34801.2435122655. The cubic root of 1211126550 is about 1065.9328378240.

Adding to 1211126550 its reverse (556211121), we get a palindrome (1767337671).

The spelling of 1211126550 in words is "one billion, two hundred eleven million, one hundred twenty-six thousand, five hundred fifty".