99311561 has 2 divisors, whose sum is σ = 99311562. Its totient is φ = 99311560.

The previous prime is 99311557. The next prime is 99311593. The reversal of 99311561 is 16511399.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52128400 + 47183161 = 7220^2 + 6869^2 .

It is a cyclic number.

It is not a de Polignac number, because 99311561 - 2² = 99311557 is a prime.

It is a super-2 number, since 2×99311561² = 19725572296513442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (99311551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49655780 + 49655781.

It is an arithmetic number, because the mean of its divisors is an integer number (49655781).

Almost surely, 2^99311561 is an apocalyptic number.

It is an amenable number.

99311561 is a deficient number, since it is larger than the sum of its proper divisors (1).

99311561 is an equidigital number, since it uses as much as digits as its factorization.

99311561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7290, while the sum is 35.

The square root of 99311561 is about 9965.5186016584. The cubic root of 99311561 is about 463.0912794079.

The spelling of 99311561 in words is "ninety-nine million, three hundred eleven thousand, five hundred sixty-one".