251991096 has 64 divisors (see below), whose sum is σ = 724039680. Its totient is φ = 71591040.

The previous prime is 251991073. The next prime is 251991107. The reversal of 251991096 is 690199152.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

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 15 ways as a sum of consecutive naturals, for example, 26265 + ... + 34551.

It is an arithmetic number, because the mean of its divisors is an integer number (11313120).

Almost surely, 2^251991096 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 251991096, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362019840).

251991096 is an abundant number, since it is smaller than the sum of its proper divisors (472048584).

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

251991096 is a wasteful number, since it uses less digits than its factorization.

251991096 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8484 (or 8480 counting only the distinct ones).

The product of its (nonzero) digits is 43740, while the sum is 42.

The square root of 251991096 is about 15874.2274142712. The cubic root of 251991096 is about 631.6285204100.

The spelling of 251991096 in words is "two hundred fifty-one million, nine hundred ninety-one thousand, ninety-six".