51731213 has 4 divisors (see below), whose sum is σ = 52103520. Its totient is φ = 51358908.

The previous prime is 51731203. The next prime is 51731237. The reversal of 51731213 is 31213715.

51731213 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51731213 - 2¹⁴ = 51714829 is a prime.

It is a super-2 number, since 2×51731213² = 5352236796902738, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51731203) 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, 185945 + ... + 186222.

It is an arithmetic number, because the mean of its divisors is an integer number (13025880).

Almost surely, 2^51731213 is an apocalyptic number.

It is an amenable number.

51731213 is a deficient number, since it is larger than the sum of its proper divisors (372307).

51731213 is a wasteful number, since it uses less digits than its factorization.

51731213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372306.

The product of its digits is 630, while the sum is 23.

The square root of 51731213 is about 7192.4413796707. The cubic root of 51731213 is about 372.6068951359.

Adding to 51731213 its reverse (31213715), we get a palindrome (82944928).

The spelling of 51731213 in words is "fifty-one million, seven hundred thirty-one thousand, two hundred thirteen".