51551557 has 2 divisors, whose sum is σ = 51551558. Its totient is φ = 51551556.

The previous prime is 51551537. The next prime is 51551567. The reversal of 51551557 is 75515515.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49999041 + 1552516 = 7071^2 + 1246^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51551557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51551537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25775778 + 25775779.

It is an arithmetic number, because the mean of its divisors is an integer number (25775779).

Almost surely, 2^51551557 is an apocalyptic number.

It is an amenable number.

51551557 is a deficient number, since it is larger than the sum of its proper divisors (1).

51551557 is an equidigital number, since it uses as much as digits as its factorization.

51551557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21875, while the sum is 34.

The square root of 51551557 is about 7179.9412950246. The cubic root of 51551557 is about 372.1750558718.

The spelling of 51551557 in words is "fifty-one million, five hundred fifty-one thousand, five hundred fifty-seven".