99731681 has 8 divisors (see below), whose sum is σ = 117656064. Its totient is φ = 82726560.

The previous prime is 99731659. The next prime is 99731693. The reversal of 99731681 is 18613799.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 99731681 - 2²⁶ = 32622817 is a prime.

It is a super-2 number, since 2×99731681² = 19892816390171522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99731081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 229580 + ... + 230013.

It is an arithmetic number, because the mean of its divisors is an integer number (14707008).

Almost surely, 2^99731681 is an apocalyptic number.

It is an amenable number.

99731681 is a deficient number, since it is larger than the sum of its proper divisors (17924383).

99731681 is a wasteful number, since it uses less digits than its factorization.

99731681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459631.

The product of its digits is 81648, while the sum is 44.

The square root of 99731681 is about 9986.5750385205. The cubic root of 99731681 is about 463.7433693470.

The spelling of 99731681 in words is "ninety-nine million, seven hundred thirty-one thousand, six hundred eighty-one".