51645231 has 12 divisors (see below), whose sum is σ = 81380520. Its totient is φ = 31300080.

The previous prime is 51645227. The next prime is 51645233. The reversal of 51645231 is 13254615.

It is not a de Polignac number, because 51645231 - 2² = 51645227 is a prime.

It is a super-2 number, since 2×51645231² = 5334459770086722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51645195 and 51645204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51645233) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 260736 + ... + 260933.

It is an arithmetic number, because the mean of its divisors is an integer number (6781710).

Almost surely, 2^51645231 is an apocalyptic number.

51645231 is a deficient number, since it is larger than the sum of its proper divisors (29735289).

51645231 is a wasteful number, since it uses less digits than its factorization.

51645231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521686 (or 521683 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 51645231 is about 7186.4616467355. The cubic root of 51645231 is about 372.4003450967.

Adding to 51645231 its reverse (13254615), we get a palindrome (64899846).

The spelling of 51645231 in words is "fifty-one million, six hundred forty-five thousand, two hundred thirty-one".