20910864 has 160 divisors (see below), whose sum is σ = 63995904. Its totient is φ = 5829120.

The previous prime is 20910863. The next prime is 20910881. The reversal of 20910864 is 46801902.

It is not an unprimeable number, because it can be changed into a prime (20910863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 444889 + ... + 444935.

Almost surely, 2^20910864 is an apocalyptic number.

20910864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20910864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31997952).

20910864 is an abundant number, since it is smaller than the sum of its proper divisors (43085040).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20910864 is a wasteful number, since it uses less digits than its factorization.

20910864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 20910864 is about 4572.8398178812. The cubic root of 20910864 is about 275.5015156872.

The spelling of 20910864 in words is "twenty million, nine hundred ten thousand, eight hundred sixty-four".