1221143550 has 48 divisors (see below), whose sum is σ = 3303752832. Its totient is φ = 296034400.

The previous prime is 1221143503. The next prime is 1221143551. The reversal of 1221143550 is 553411221.

It is a happy number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221143550.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221143551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 368394 + ... + 371693.

It is an arithmetic number, because the mean of its divisors is an integer number (68828184).

Almost surely, 2^1221143550 is an apocalyptic number.

1221143550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221143550 is an abundant number, since it is smaller than the sum of its proper divisors (2082609282).

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

1221143550 is a wasteful number, since it uses less digits than its factorization.

1221143550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740113 (or 740108 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1221143550 is about 34944.8644295553. The cubic root of 1221143550 is about 1068.8634830421.

Adding to 1221143550 its reverse (553411221), we get a palindrome (1774554771).

The spelling of 1221143550 in words is "one billion, two hundred twenty-one million, one hundred forty-three thousand, five hundred fifty".