20864860 has 48 divisors (see below), whose sum is σ = 45948672. Its totient is φ = 7948800.

The previous prime is 20864849. The next prime is 20864863. The reversal of 20864860 is 6846802.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20864863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45030 + ... + 45490.

It is an arithmetic number, because the mean of its divisors is an integer number (957264).

Almost surely, 2^20864860 is an apocalyptic number.

20864860 is a gapful number since it is divisible by the number (20) 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 20864860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22974336).

20864860 is an abundant number, since it is smaller than the sum of its proper divisors (25083812).

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

20864860 is a wasteful number, since it uses less digits than its factorization.

20864860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574 (or 572 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 34.

The square root of 20864860 is about 4567.8069136074. The cubic root of 20864860 is about 275.2993324661.

The spelling of 20864860 in words is "twenty million, eight hundred sixty-four thousand, eight hundred sixty".