20908881 has 16 divisors (see below), whose sum is σ = 35401600. Its totient is φ = 11947824.

The previous prime is 20908837. The next prime is 20908883. The reversal of 20908881 is 18880902.

It is not a de Polignac number, because 20908881 - 2⁷ = 20908753 is a prime.

It is a super-2 number, since 2×20908881² = 874362609344322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20908883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55126 + ... + 55503.

It is an arithmetic number, because the mean of its divisors is an integer number (2212600).

Almost surely, 2^20908881 is an apocalyptic number.

20908881 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20908881 is a deficient number, since it is larger than the sum of its proper divisors (14492719).

20908881 is a wasteful number, since it uses less digits than its factorization.

20908881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110645 (or 110639 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 20908881 is about 4572.6229890513. The cubic root of 20908881 is about 275.4928067090.

The spelling of 20908881 in words is "twenty million, nine hundred eight thousand, eight hundred eighty-one".