1211261312550 has 192 divisors, whose sum is σ = 3058131124224. Its totient is φ = 317244211200.

The previous prime is 1211261312549. The next prime is 1211261312579. The reversal of 1211261312550 is 552131621121.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 886071967 + ... + 886073333.

It is an arithmetic number, because the mean of its divisors is an integer number (15927766272).

Almost surely, 2^{1211261312550} is an apocalyptic number.

1211261312550 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 1211261312550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1529065562112).

1211261312550 is an abundant number, since it is smaller than the sum of its proper divisors (1846869811674).

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

1211261312550 is a wasteful number, since it uses less digits than its factorization.

1211261312550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1943 (or 1938 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

Adding to 1211261312550 its reverse (552131621121), we get a palindrome (1763392933671).

The spelling of 1211261312550 in words is "one trillion, two hundred eleven billion, two hundred sixty-one million, three hundred twelve thousand, five hundred fifty".