99861985 has 16 divisors (see below), whose sum is σ = 122245200. Its totient is φ = 78299136.

The previous prime is 99861973. The next prime is 99862013. The reversal of 99861985 is 58916899.

It can be written as a sum of positive squares in 8 ways, for example, as 1936 + 99860049 = 44^2 + 9993^2 .

It is a 3-Lehmer number, since φ(99861985) divides (99861985-1)³.

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 99861985 - 2⁷ = 99861857 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51921 + ... + 53809.

It is an arithmetic number, because the mean of its divisors is an integer number (7640325).

It is a Poulet number, since it divides 2^99861984-1.

Almost surely, 2^99861985 is an apocalyptic number.

It is an amenable number.

99861985 is a deficient number, since it is larger than the sum of its proper divisors (22383215).

99861985 is a wasteful number, since it uses less digits than its factorization.

99861985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100.

The product of its digits is 1399680, while the sum is 55.

The square root of 99861985 is about 9993.0968673380. The cubic root of 99861985 is about 463.9452487542.

The spelling of 99861985 in words is "ninety-nine million, eight hundred sixty-one thousand, nine hundred eighty-five".