251914640 has 80 divisors (see below), whose sum is σ = 608824128. Its totient is φ = 96864768.

The previous prime is 251914633. The next prime is 251914667. The reversal of 251914640 is 46419152.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 251914597 and 251914606.

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 15 ways as a sum of consecutive naturals, for example, 229934 + ... + 231026.

Almost surely, 2^251914640 is an apocalyptic number.

251914640 is a gapful number since it is divisible by the number (20) 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 251914640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304412064).

251914640 is an abundant number, since it is smaller than the sum of its proper divisors (356909488).

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

251914640 is a wasteful number, since it uses less digits than its factorization.

251914640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1216 (or 1210 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 251914640 is about 15871.8190513879. The cubic root of 251914640 is about 631.5646336620.

The spelling of 251914640 in words is "two hundred fifty-one million, nine hundred fourteen thousand, six hundred forty".