51513631 has 4 divisors (see below), whose sum is σ = 55476232. Its totient is φ = 47551032.

The previous prime is 51513619. The next prime is 51513647. The reversal of 51513631 is 13631515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13631515 = 5 ⋅2726303.

It is a cyclic number.

It is not a de Polignac number, because 51513631 - 2¹⁷ = 51382559 is a prime.

It is a super-2 number, since 2×51513631² = 5307308357608322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51513596 and 51513605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51513601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1981281 + ... + 1981306.

It is an arithmetic number, because the mean of its divisors is an integer number (13869058).

Almost surely, 2^51513631 is an apocalyptic number.

51513631 is a deficient number, since it is larger than the sum of its proper divisors (3962601).

51513631 is a wasteful number, since it uses less digits than its factorization.

51513631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3962600.

The product of its digits is 1350, while the sum is 25.

The square root of 51513631 is about 7177.2997011411. The cubic root of 51513631 is about 372.0837649076.

The spelling of 51513631 in words is "fifty-one million, five hundred thirteen thousand, six hundred thirty-one".