1251131868 has 72 divisors (see below), whose sum is σ = 3618244448. Its totient is φ = 357084288.

The previous prime is 1251131863. The next prime is 1251131879. The reversal of 1251131868 is 8681311521.

It is a super-2 number, since 2×1251131868² = 3130661902250338848, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251131863) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 303630 + ... + 307722.

Almost surely, 2^1251131868 is an apocalyptic number.

1251131868 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1251131868 is an abundant number, since it is smaller than the sum of its proper divisors (2367112580).

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

1251131868 is a wasteful number, since it uses less digits than its factorization.

1251131868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5323 (or 5318 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 1251131868 is about 35371.3424681620. The cubic root of 1251131868 is about 1077.5423850195.

The spelling of 1251131868 in words is "one billion, two hundred fifty-one million, one hundred thirty-one thousand, eight hundred sixty-eight".