1251279120 has 640 divisors, whose sum is σ = 5183668224. Its totient is φ = 242491392.

The previous prime is 1251279109. The next prime is 1251279149. The reversal of 1251279120 is 219721521.

It is a super-2 number, since 2×1251279120² = 3131398872295948800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 23609014 + ... + 23609066.

Almost surely, 2^1251279120 is an apocalyptic number.

1251279120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1251279120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2591834112).

1251279120 is an abundant number, since it is smaller than the sum of its proper divisors (3932389104).

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

1251279120 is a wasteful number, since it uses less digits than its factorization.

1251279120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 30.

The square root of 1251279120 is about 35373.4239224873. The cubic root of 1251279120 is about 1077.5846571548.

The spelling of 1251279120 in words is "one billion, two hundred fifty-one million, two hundred seventy-nine thousand, one hundred twenty".