51591557 has 2 divisors, whose sum is σ = 51591558. Its totient is φ = 51591556.

The previous prime is 51591539. The next prime is 51591569. The reversal of 51591557 is 75519515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29931841 + 21659716 = 5471^2 + 4654^2 .

It is a cyclic number.

It is not a de Polignac number, because 51591557 - 2¹⁰ = 51590533 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51591557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51591577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25795778 + 25795779.

It is an arithmetic number, because the mean of its divisors is an integer number (25795779).

Almost surely, 2^51591557 is an apocalyptic number.

It is an amenable number.

51591557 is a deficient number, since it is larger than the sum of its proper divisors (1).

51591557 is an equidigital number, since it uses as much as digits as its factorization.

51591557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39375, while the sum is 38.

The square root of 51591557 is about 7182.7262929893. The cubic root of 51591557 is about 372.2712906213.

The spelling of 51591557 in words is "fifty-one million, five hundred ninety-one thousand, five hundred fifty-seven".