99431917631 has 4 divisors (see below), whose sum is σ = 99432838200. Its totient is φ = 99430997064.

The previous prime is 99431917609. The next prime is 99431917649. The reversal of 99431917631 is 13671913499.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 13671913499 = 257 ⋅53198107.

It is a cyclic number.

It is not a de Polignac number, because 99431917631 - 2²² = 99427723327 is a prime.

It is a super-2 number, since 2×99431917631² (a number of 23 digits) 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 (99431917681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 272816 + ... + 522773.

It is an arithmetic number, because the mean of its divisors is an integer number (24858209550).

Almost surely, 2^99431917631 is an apocalyptic number.

99431917631 is a deficient number, since it is larger than the sum of its proper divisors (920569).

99431917631 is a wasteful number, since it uses less digits than its factorization.

99431917631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920568.

The product of its digits is 1102248, while the sum is 53.

The spelling of 99431917631 in words is "ninety-nine billion, four hundred thirty-one million, nine hundred seventeen thousand, six hundred thirty-one".