251491996 has 48 divisors (see below), whose sum is σ = 516632256. Its totient is φ = 104891904.

The previous prime is 251491969. The next prime is 251492047. The reversal of 251491996 is 699194152.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202690 + ... + 203926.

It is an arithmetic number, because the mean of its divisors is an integer number (10763172).

Almost surely, 2^251491996 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 251491996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (258316128).

251491996 is an abundant number, since it is smaller than the sum of its proper divisors (265140260).

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

251491996 is a wasteful number, since it uses less digits than its factorization.

251491996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1438 (or 1436 counting only the distinct ones).

The product of its digits is 174960, while the sum is 46.

The square root of 251491996 is about 15858.4991723681. The cubic root of 251491996 is about 631.2112382695.

The spelling of 251491996 in words is "two hundred fifty-one million, four hundred ninety-one thousand, nine hundred ninety-six".