20718881 has 8 divisors (see below), whose sum is σ = 21441024. Its totient is φ = 20000160.

The previous prime is 20718871. The next prime is 20718913. The reversal of 20718881 is 18881702.

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 20718881 - 2¹⁴ = 20702497 is a prime.

It is a super-2 number, since 2×20718881² = 858544059784322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20718851) 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, 19541 + ... + 20573.

It is an arithmetic number, because the mean of its divisors is an integer number (2680128).

Almost surely, 2^20718881 is an apocalyptic number.

It is an amenable number.

20718881 is a deficient number, since it is larger than the sum of its proper divisors (722143).

20718881 is a wasteful number, since it uses less digits than its factorization.

20718881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1711.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 20718881 is about 4551.7997539435. The cubic root of 20718881 is about 274.6557941452.

The spelling of 20718881 in words is "twenty million, seven hundred eighteen thousand, eight hundred eighty-one".