251221432404 has 24 divisors (see below), whose sum is σ = 586196170560. Its totient is φ = 83738644864.

The previous prime is 251221432387. The next prime is 251221432409. The reversal of 251221432404 is 404234122152.

It is a happy number.

It is a super-2 number, since 2×251221432404² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251221432409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 414412 + ... + 821084.

It is an arithmetic number, because the mean of its divisors is an integer number (24424840440).

Almost surely, 2^251221432404 is an apocalyptic number.

It is an amenable number.

251221432404 is an abundant number, since it is smaller than the sum of its proper divisors (334974738156).

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

251221432404 is a wasteful number, since it uses less digits than its factorization.

251221432404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458159 (or 458157 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

Adding to 251221432404 its reverse (404234122152), we get a palindrome (655455554556).

The spelling of 251221432404 in words is "two hundred fifty-one billion, two hundred twenty-one million, four hundred thirty-two thousand, four hundred four".