99881691 has 32 divisors (see below), whose sum is σ = 164451840. Its totient is φ = 52510464.

The previous prime is 99881687. The next prime is 99881711. The reversal of 99881691 is 19618899.

It is a happy number.

It is not a de Polignac number, because 99881691 - 2² = 99881687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99881671) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 155016 + ... + 155658.

It is an arithmetic number, because the mean of its divisors is an integer number (5139120).

Almost surely, 2^99881691 is an apocalyptic number.

99881691 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

99881691 is a deficient number, since it is larger than the sum of its proper divisors (64570149).

99881691 is a wasteful number, since it uses less digits than its factorization.

99881691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235.

The product of its digits is 279936, while the sum is 51.

The square root of 99881691 is about 9994.0827993368. The cubic root of 99881691 is about 463.9757638822.

The spelling of 99881691 in words is "ninety-nine million, eight hundred eighty-one thousand, six hundred ninety-one".