51322440 has 128 divisors (see below), whose sum is σ = 167650560. Its totient is φ = 12493824.

The previous prime is 51322423. The next prime is 51322459. The reversal of 51322440 is 4422315.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 260422 + ... + 260618.

It is an arithmetic number, because the mean of its divisors is an integer number (1309770).

Almost surely, 2^51322440 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 51322440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83825280).

51322440 is an abundant number, since it is smaller than the sum of its proper divisors (116328120).

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

51322440 is a wasteful number, since it uses less digits than its factorization.

51322440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 51322440 is about 7163.9681741337. The cubic root of 51322440 is about 371.6228690394.

Adding to 51322440 its reverse (4422315), we get a palindrome (55744755).

The spelling of 51322440 in words is "fifty-one million, three hundred twenty-two thousand, four hundred forty".