51516431 has 2 divisors, whose sum is σ = 51516432. Its totient is φ = 51516430.

The previous prime is 51516419. The next prime is 51516433. The reversal of 51516431 is 13461515.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51516431 - 2¹⁰ = 51515407 is a prime.

It is a super-2 number, since 2×51516431² = 5307885325955522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 51516433, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51516431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51516433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25758215 + 25758216.

It is an arithmetic number, because the mean of its divisors is an integer number (25758216).

Almost surely, 2^51516431 is an apocalyptic number.

51516431 is a deficient number, since it is larger than the sum of its proper divisors (1).

51516431 is an equidigital number, since it uses as much as digits as its factorization.

51516431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1800, while the sum is 26.

The square root of 51516431 is about 7177.4947579222. The cubic root of 51516431 is about 372.0905062668.

Adding to 51516431 its reverse (13461515), we get a palindrome (64977946).

The spelling of 51516431 in words is "fifty-one million, five hundred sixteen thousand, four hundred thirty-one".