51531240 has 32 divisors (see below), whose sum is σ = 154594080. Its totient is φ = 13741632.

The previous prime is 51531217. The next prime is 51531251. The reversal of 51531240 is 4213515.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214594 + ... + 214833.

It is an arithmetic number, because the mean of its divisors is an integer number (4831065).

Almost surely, 2^51531240 is an apocalyptic number.

It is an amenable number.

51531240 is an abundant number, since it is smaller than the sum of its proper divisors (103062840).

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

51531240 is a wasteful number, since it uses less digits than its factorization.

51531240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429441 (or 429437 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 51531240 is about 7178.5263111589. The cubic root of 51531240 is about 372.1261567721.

Adding to 51531240 its reverse (4213515), we get a palindrome (55744755).

The spelling of 51531240 in words is "fifty-one million, five hundred thirty-one thousand, two hundred forty".