8515561 has 2 divisors, whose sum is σ = 8515562. Its totient is φ = 8515560.

The previous prime is 8515541. The next prime is 8515597. The reversal of 8515561 is 1655158.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7425625 + 1089936 = 2725^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 8515561 - 2⁷ = 8515433 is a prime.

It is not a weakly prime, because it can be changed into another prime (8515511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4257780 + 4257781.

It is an arithmetic number, because the mean of its divisors is an integer number (4257781).

Almost surely, 2^8515561 is an apocalyptic number.

It is an amenable number.

8515561 is a deficient number, since it is larger than the sum of its proper divisors (1).

8515561 is an equidigital number, since it uses as much as digits as its factorization.

8515561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6000, while the sum is 31.

The square root of 8515561 is about 2918.1434166264. The cubic root of 8515561 is about 204.2072176754.

The spelling of 8515561 in words is "eight million, five hundred fifteen thousand, five hundred sixty-one".