51431213 has 2 divisors, whose sum is σ = 51431214. Its totient is φ = 51431212.

The previous prime is 51431189. The next prime is 51431249. The reversal of 51431213 is 31213415.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49589764 + 1841449 = 7042^2 + 1357^2 .

It is a cyclic number.

It is not a de Polignac number, because 51431213 - 2¹⁰ = 51430189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51431293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25715606 + 25715607.

It is an arithmetic number, because the mean of its divisors is an integer number (25715607).

Almost surely, 2^51431213 is an apocalyptic number.

It is an amenable number.

51431213 is a deficient number, since it is larger than the sum of its proper divisors (1).

51431213 is an equidigital number, since it uses as much as digits as its factorization.

51431213 is an evil number, because the sum of its binary digits is even.

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

The square root of 51431213 is about 7171.5558284099. Note that the first 3 decimals coincide. The cubic root of 51431213 is about 371.8852234837.

Adding to 51431213 its reverse (31213415), we get a palindrome (82644628).

The spelling of 51431213 in words is "fifty-one million, four hundred thirty-one thousand, two hundred thirteen".