1251613640 has 16 divisors (see below), whose sum is σ = 2816130780. Its totient is φ = 500645440.

The previous prime is 1251613637. The next prime is 1251613663. The reversal of 1251613640 is 463161521.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 1251319876 + 293764 = 35374^2 + 542^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15645131 + ... + 15645210.

Almost surely, 2^1251613640 is an apocalyptic number.

1251613640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1251613640 is an abundant number, since it is smaller than the sum of its proper divisors (1564517140).

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

1251613640 is a wasteful number, since it uses less digits than its factorization.

1251613640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31290352 (or 31290348 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 1251613640 is about 35378.1520150502. The cubic root of 1251613640 is about 1077.6806766321.

The spelling of 1251613640 in words is "one billion, two hundred fifty-one million, six hundred thirteen thousand, six hundred forty".