251283640 has 32 divisors (see below), whose sum is σ = 565902000. Its totient is φ = 100422144.

The previous prime is 251283631. The next prime is 251283649. The reversal of 251283640 is 46382152.

It is an interprime number because it is at equal distance from previous prime (251283631) and next prime (251283649).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251283649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57451 + ... + 61669.

Almost surely, 2^251283640 is an apocalyptic number.

251283640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251283640 is an abundant number, since it is smaller than the sum of its proper divisors (314618360).

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

251283640 is a wasteful number, since it uses less digits than its factorization.

251283640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5719 (or 5715 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 251283640 is about 15851.9285892916. The cubic root of 251283640 is about 631.0368748872.

The spelling of 251283640 in words is "two hundred fifty-one million, two hundred eighty-three thousand, six hundred forty".