251940864 has 208 divisors, whose sum is σ = 802062720. Its totient is φ = 68812800.

The previous prime is 251940791. The next prime is 251940869. The reversal of 251940864 is 468049152.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251940869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2494414 + ... + 2494514.

Almost surely, 2^251940864 is an apocalyptic number.

251940864 is a gapful number since it is divisible by the number (24) 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 251940864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (401031360).

251940864 is an abundant number, since it is smaller than the sum of its proper divisors (550121856).

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

251940864 is a wasteful number, since it uses less digits than its factorization.

251940864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 39.

The square root of 251940864 is about 15872.6451481787. The cubic root of 251940864 is about 631.5865479319.

The spelling of 251940864 in words is "two hundred fifty-one million, nine hundred forty thousand, eight hundred sixty-four".