251234320440 has 64 divisors (see below), whose sum is σ = 759456466560. Its totient is φ = 66484396160.

The previous prime is 251234320433. The next prime is 251234320457. The reversal of 251234320440 is 44023432152.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 251234320398 and 251234320407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7975194 + ... + 8006633.

It is an arithmetic number, because the mean of its divisors is an integer number (11866507290).

Almost surely, 2^251234320440 is an apocalyptic number.

251234320440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251234320440 is an abundant number, since it is smaller than the sum of its proper divisors (508222146120).

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

251234320440 is a wasteful number, since it uses less digits than its factorization.

251234320440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15981972 (or 15981968 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 30.

Adding to 251234320440 its reverse (44023432152), we get a palindrome (295257752592).

The spelling of 251234320440 in words is "two hundred fifty-one billion, two hundred thirty-four million, three hundred twenty thousand, four hundred forty".