51538531 has 4 divisors (see below), whose sum is σ = 56223864. Its totient is φ = 46853200.

The previous prime is 51538519. The next prime is 51538541. The reversal of 51538531 is 13583515.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51538531 - 2¹¹ = 51536483 is a prime.

It is a super-2 number, since 2×51538531² = 5312440355275922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51538493 and 51538502.

It is not an unprimeable number, because it can be changed into a prime (51538541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2342650 + ... + 2342671.

It is an arithmetic number, because the mean of its divisors is an integer number (14055966).

Almost surely, 2^51538531 is an apocalyptic number.

51538531 is a deficient number, since it is larger than the sum of its proper divisors (4685333).

51538531 is a wasteful number, since it uses less digits than its factorization.

51538531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4685332.

The product of its digits is 9000, while the sum is 31.

The square root of 51538531 is about 7179.0341272347. The cubic root of 51538531 is about 372.1437062810.

The spelling of 51538531 in words is "fifty-one million, five hundred thirty-eight thousand, five hundred thirty-one".