20864040 has 32 divisors (see below), whose sum is σ = 62592480. Its totient is φ = 5563712.

The previous prime is 20864009. The next prime is 20864047. The reversal of 20864040 is 4046802.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20864040.

It is not an unprimeable number, because it can be changed into a prime (20864047) 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, 86814 + ... + 87053.

It is an arithmetic number, because the mean of its divisors is an integer number (1956015).

Almost surely, 2^20864040 is an apocalyptic number.

20864040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20864040 is an abundant number, since it is smaller than the sum of its proper divisors (41728440).

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

20864040 is a wasteful number, since it uses less digits than its factorization.

20864040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173881 (or 173877 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 20864040 is about 4567.7171541154. The cubic root of 20864040 is about 275.2957259492.

The spelling of 20864040 in words is "twenty million, eight hundred sixty-four thousand, forty".