51611631 has 4 divisors (see below), whose sum is σ = 68815512. Its totient is φ = 34407752.

The previous prime is 51611629. The next prime is 51611647. The reversal of 51611631 is 13611615.

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 51611631 - 2¹ = 51611629 is a prime.

It is a super-2 number, since 2×51611631² = 5327520908960322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51611611) 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, 8601936 + ... + 8601941.

It is an arithmetic number, because the mean of its divisors is an integer number (17203878).

Almost surely, 2^51611631 is an apocalyptic number.

51611631 is a deficient number, since it is larger than the sum of its proper divisors (17203881).

51611631 is a wasteful number, since it uses less digits than its factorization.

51611631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17203880.

The product of its digits is 540, while the sum is 24.

The square root of 51611631 is about 7184.1235373565. The cubic root of 51611631 is about 372.3195672858.

The spelling of 51611631 in words is "fifty-one million, six hundred eleven thousand, six hundred thirty-one".