1211553880 has 32 divisors (see below), whose sum is σ = 2819998800. Its totient is φ = 467910016.

The previous prime is 1211553859. The next prime is 1211553907. The reversal of 1211553880 is 883551121.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 521062 + ... + 523381.

Almost surely, 2^1211553880 is an apocalyptic number.

1211553880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211553880 is an abundant number, since it is smaller than the sum of its proper divisors (1608444920).

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

1211553880 is a wasteful number, since it uses less digits than its factorization.

1211553880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044483 (or 1044479 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 34.

The square root of 1211553880 is about 34807.3825502579. The cubic root of 1211553880 is about 1066.0581898546.

The spelling of 1211553880 in words is "one billion, two hundred eleven million, five hundred fifty-three thousand, eight hundred eighty".