999917631 has 12 divisors (see below), whose sum is σ = 1446689608. Its totient is φ = 665520624.

The previous prime is 999917623. The next prime is 999917669. The reversal of 999917631 is 136719999.

It is not a de Polignac number, because 999917631 - 2³ = 999917623 is a prime.

It is a super-2 number, since 2×999917631² = 1999670537569304322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999917671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85105 + ... + 96138.

Almost surely, 2^999917631 is an apocalyptic number.

999917631 is a deficient number, since it is larger than the sum of its proper divisors (446771977).

999917631 is a wasteful number, since it uses less digits than its factorization.

999917631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181862 (or 181859 counting only the distinct ones).

The product of its digits is 826686, while the sum is 54.

The square root of 999917631 is about 31621.4742066210. The cubic root of 999917631 is about 999.9725429128.

The spelling of 999917631 in words is "nine hundred ninety-nine million, nine hundred seventeen thousand, six hundred thirty-one".