99971985 has 32 divisors (see below), whose sum is σ = 172167552. Its totient is φ = 49351680.

The previous prime is 99971953. The next prime is 99972013. The reversal of 99971985 is 58917999.

It is not a de Polignac number, because 99971985 - 2⁵ = 99971953 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12342 + ... + 18768.

It is an arithmetic number, because the mean of its divisors is an integer number (5380236).

Almost surely, 2^99971985 is an apocalyptic number.

It is an amenable number.

99971985 is a deficient number, since it is larger than the sum of its proper divisors (72195567).

99971985 is a wasteful number, since it uses less digits than its factorization.

99971985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6513.

The product of its digits is 1837080, while the sum is 57.

The square root of 99971985 is about 9998.5991518812. The cubic root of 99971985 is about 464.1155346093.

The spelling of 99971985 in words is "ninety-nine million, nine hundred seventy-one thousand, nine hundred eighty-five".