51620231 has 4 divisors (see below), whose sum is σ = 55591032. Its totient is φ = 47649432.

The previous prime is 51620227. The next prime is 51620237. The reversal of 51620231 is 13202615.

51620231 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 51620231 - 2² = 51620227 is a prime.

It is a super-2 number, since 2×51620231² = 5329296496986722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51620237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1985381 + ... + 1985406.

It is an arithmetic number, because the mean of its divisors is an integer number (13897758).

Almost surely, 2^51620231 is an apocalyptic number.

51620231 is a deficient number, since it is larger than the sum of its proper divisors (3970801).

51620231 is a wasteful number, since it uses less digits than its factorization.

51620231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3970800.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 51620231 is about 7184.7220544709. The cubic root of 51620231 is about 372.3402458963.

Adding to 51620231 its reverse (13202615), we get a palindrome (64822846).

The spelling of 51620231 in words is "fifty-one million, six hundred twenty thousand, two hundred thirty-one".