251906816 has 72 divisors (see below), whose sum is σ = 608539680. Its totient is φ = 101597184.

The previous prime is 251906779. The next prime is 251906819. The reversal of 251906816 is 618609152.

It is a self number, because there is not a number n which added to its sum of digits gives 251906816.

It is not an unprimeable number, because it can be changed into a prime (251906819) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 26330 + ... + 34598.

It is an arithmetic number, because the mean of its divisors is an integer number (8451940).

Almost surely, 2^251906816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251906816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304269840).

251906816 is an abundant number, since it is smaller than the sum of its proper divisors (356632864).

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

251906816 is an equidigital number, since it uses as much as digits as its factorization.

251906816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8309 (or 8295 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 251906816 is about 15871.5725748900. The cubic root of 251906816 is about 631.5580951868.

The spelling of 251906816 in words is "two hundred fifty-one million, nine hundred six thousand, eight hundred sixteen".