51205631 has 4 divisors (see below), whose sum is σ = 51907152. Its totient is φ = 50504112.

The previous prime is 51205603. The next prime is 51205633. The reversal of 51205631 is 13650215.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51205631 is a prime.

It is a super-2 number, since 2×51205631² = 5244033292216322, 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 = 51205597 and 51205606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51205633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 350651 + ... + 350796.

It is an arithmetic number, because the mean of its divisors is an integer number (12976788).

Almost surely, 2^51205631 is an apocalyptic number.

51205631 is a deficient number, since it is larger than the sum of its proper divisors (701521).

51205631 is an equidigital number, since it uses as much as digits as its factorization.

51205631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701520.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 51205631 is about 7155.8109952681. The cubic root of 51205631 is about 371.3407190998.

Adding to 51205631 its reverse (13650215), we get a palindrome (64855846).

The spelling of 51205631 in words is "fifty-one million, two hundred five thousand, six hundred thirty-one".