20672809 has 16 divisors (see below), whose sum is σ = 22125312. Its totient is φ = 19289088.

The previous prime is 20672807. The next prime is 20672843. The reversal of 20672809 is 90827602.

It is a cyclic number.

It is not a de Polignac number, because 20672809 - 2¹ = 20672807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20672803) 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, 107017 + ... + 107209.

It is an arithmetic number, because the mean of its divisors is an integer number (1382832).

Almost surely, 2^20672809 is an apocalyptic number.

It is an amenable number.

20672809 is a deficient number, since it is larger than the sum of its proper divisors (1452503).

20672809 is a wasteful number, since it uses less digits than its factorization.

20672809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 20672809 is about 4546.7360820703. The cubic root of 20672809 is about 274.4520615730.

The spelling of 20672809 in words is "twenty million, six hundred seventy-two thousand, eight hundred nine".