51331224 has 48 divisors (see below), whose sum is σ = 149283000. Its totient is φ = 14665728.

The previous prime is 51331223. The next prime is 51331229. The reversal of 51331224 is 42213315.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 51331224.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51331223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20649 + ... + 23000.

Almost surely, 2^51331224 is an apocalyptic number.

It is an amenable number.

51331224 is an abundant number, since it is smaller than the sum of its proper divisors (97951776).

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

51331224 is a wasteful number, since it uses less digits than its factorization.

51331224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43672 (or 43661 counting only the distinct ones).

The product of its digits is 720, while the sum is 21.

The square root of 51331224 is about 7164.5812159539. The cubic root of 51331224 is about 371.6440693114.

Adding to 51331224 its reverse (42213315), we get a palindrome (93544539).

The spelling of 51331224 in words is "fifty-one million, three hundred thirty-one thousand, two hundred twenty-four".