20899731 has 8 divisors (see below), whose sum is σ = 27904464. Its totient is φ = 13914080.

The previous prime is 20899721. The next prime is 20899733. The reversal of 20899731 is 13799802.

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

It is a cyclic number.

It is not a de Polignac number, because 20899731 - 2⁵ = 20899699 is a prime.

It is a super-2 number, since 2×20899731² = 873597511744722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20899731.

It is not an unprimeable number, because it can be changed into a prime (20899733) 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, 1980 + ... + 6761.

It is an arithmetic number, because the mean of its divisors is an integer number (3488058).

Almost surely, 2^20899731 is an apocalyptic number.

20899731 is a deficient number, since it is larger than the sum of its proper divisors (7004733).

20899731 is an equidigital number, since it uses as much as digits as its factorization.

20899731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9541.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 20899731 is about 4571.6223597318. The cubic root of 20899731 is about 275.4526144261.

The spelling of 20899731 in words is "twenty million, eight hundred ninety-nine thousand, seven hundred thirty-one".