51015509 has 2 divisors, whose sum is σ = 51015510. Its totient is φ = 51015508.

The previous prime is 51015457. The next prime is 51015511. The reversal of 51015509 is 90551015.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34774609 + 16240900 = 5897^2 + 4030^2 .

It is a cyclic number.

It is not a de Polignac number, because 51015509 - 2⁸ = 51015253 is a prime.

Together with 51015511, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_3058361 and since 51015509 and 3058361 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51015529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25507754 + 25507755.

It is an arithmetic number, because the mean of its divisors is an integer number (25507755).

Almost surely, 2^51015509 is an apocalyptic number.

It is an amenable number.

51015509 is a deficient number, since it is larger than the sum of its proper divisors (1).

51015509 is an equidigital number, since it uses as much as digits as its factorization.

51015509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1125, while the sum is 26.

The square root of 51015509 is about 7142.5141931956. The cubic root of 51015509 is about 370.8805639909.

The spelling of 51015509 in words is "fifty-one million, fifteen thousand, five hundred nine".