8615867521 has 2 divisors, whose sum is σ = 8615867522. Its totient is φ = 8615867520.

The previous prime is 8615867503. The next prime is 8615867587. The reversal of 8615867521 is 1257685168.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4494227521 + 4121640000 = 67039^2 + 64200^2 .

It is a cyclic number.

It is not a de Polignac number, because 8615867521 - 2¹⁷ = 8615736449 is a prime.

It is not a weakly prime, because it can be changed into another prime (8615867501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4307933760 + 4307933761.

It is an arithmetic number, because the mean of its divisors is an integer number (4307933761).

Almost surely, 2^8615867521 is an apocalyptic number.

It is an amenable number.

8615867521 is a deficient number, since it is larger than the sum of its proper divisors (1).

8615867521 is an equidigital number, since it uses as much as digits as its factorization.

8615867521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 806400, while the sum is 49.

The square root of 8615867521 is about 92821.6974688569. The cubic root of 8615867521 is about 2050.0588934895.

The spelling of 8615867521 in words is "eight billion, six hundred fifteen million, eight hundred sixty-seven thousand, five hundred twenty-one".