99991658 has 16 divisors (see below), whose sum is σ = 161707560. Its totient is φ = 46097856.

The previous prime is 99991609. The next prime is 99991667. The reversal of 99991658 is 85619999.

It can be written as a sum of positive squares in 4 ways, for example, as 65334889 + 34656769 = 8083^2 + 5887^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30608 + ... + 33716.

Almost surely, 2^99991658 is an apocalyptic number.

99991658 is a deficient number, since it is larger than the sum of its proper divisors (61715902).

99991658 is a wasteful number, since it uses less digits than its factorization.

99991658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4361.

The product of its digits is 1574640, while the sum is 56.

The square root of 99991658 is about 9999.5828913010. The cubic root of 99991658 is about 464.1459762910.

The spelling of 99991658 in words is "ninety-nine million, nine hundred ninety-one thousand, six hundred fifty-eight".