1251206920 has 32 divisors (see below), whose sum is σ = 2842557120. Its totient is φ = 495622080.

The previous prime is 1251206909. The next prime is 1251206939. The reversal of 1251206920 is 296021521.

It is a super-5 number, since 5×1251206920⁵ (a number of 47 digits) contains 55555 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147726 + ... + 155965.

It is an arithmetic number, because the mean of its divisors is an integer number (88829910).

Almost surely, 2^1251206920 is an apocalyptic number.

1251206920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1251206920 is an abundant number, since it is smaller than the sum of its proper divisors (1591350200).

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

1251206920 is a wasteful number, since it uses less digits than its factorization.

1251206920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303805 (or 303801 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 1251206920 is about 35372.4033675972. The cubic root of 1251206920 is about 1077.5639308683.

The spelling of 1251206920 in words is "one billion, two hundred fifty-one million, two hundred six thousand, nine hundred twenty".