20815680 has 56 divisors (see below), whose sum is σ = 66092832. Its totient is φ = 5550592.

The previous prime is 20815679. The next prime is 20815687. The reversal of 20815680 is 8651802.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20815687) 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 7 ways as a sum of consecutive naturals, for example, 9882 + ... + 11801.

Almost surely, 2^20815680 is an apocalyptic number.

20815680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20815680 is an abundant number, since it is smaller than the sum of its proper divisors (45277152).

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

20815680 is a wasteful number, since it uses less digits than its factorization.

20815680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21703 (or 21693 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 20815680 is about 4562.4204102647. The cubic root of 20815680 is about 275.0828620821.

The spelling of 20815680 in words is "twenty million, eight hundred fifteen thousand, six hundred eighty".