51431540 has 24 divisors (see below), whose sum is σ = 109779432. Its totient is φ = 20234880.

The previous prime is 51431521. The next prime is 51431563. The reversal of 51431540 is 4513415.

It can be written as a sum of positive squares in 4 ways, for example, as 1106704 + 50324836 = 1052^2 + 7094^2 .

It is a congruent number.

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, 19859 + ... + 22298.

It is an arithmetic number, because the mean of its divisors is an integer number (4574143).

Almost surely, 2^51431540 is an apocalyptic number.

It is an amenable number.

51431540 is an abundant number, since it is smaller than the sum of its proper divisors (58347892).

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

51431540 is a wasteful number, since it uses less digits than its factorization.

51431540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42227 (or 42225 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 51431540 is about 7171.5786267739. The cubic root of 51431540 is about 371.8860116317.

Adding to 51431540 its reverse (4513415), we get a palindrome (55944955).

The spelling of 51431540 in words is "fifty-one million, four hundred thirty-one thousand, five hundred forty".