20971807 has 2 divisors, whose sum is σ = 20971808. Its totient is φ = 20971806.

The previous prime is 20971799. The next prime is 20971889. The reversal of 20971807 is 70817902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20971807 - 2³ = 20971799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20971507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10485903 + 10485904.

It is an arithmetic number, because the mean of its divisors is an integer number (10485904).

Almost surely, 2^20971807 is an apocalyptic number.

20971807 is a deficient number, since it is larger than the sum of its proper divisors (1).

20971807 is an equidigital number, since it uses as much as digits as its factorization.

20971807 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 20971807 is about 4579.4985533353. The cubic root of 20971807 is about 275.7688982992.

The spelling of 20971807 in words is "twenty million, nine hundred seventy-one thousand, eight hundred seven".