251840664 has 80 divisors (see below), whose sum is σ = 720482400. Its totient is φ = 82150848.

The previous prime is 251840651. The next prime is 251840671. The reversal of 251840664 is 466048152.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 26322 + ... + 34590.

It is an arithmetic number, because the mean of its divisors is an integer number (9006030).

Almost surely, 2^251840664 is an apocalyptic number.

251840664 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 251840664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (360241200).

251840664 is an abundant number, since it is smaller than the sum of its proper divisors (468641736).

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

251840664 is a wasteful number, since it uses less digits than its factorization.

251840664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8334 (or 8321 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 251840664 is about 15869.4884605648. The cubic root of 251840664 is about 631.5028069001.

The spelling of 251840664 in words is "two hundred fifty-one million, eight hundred forty thousand, six hundred sixty-four".