20970009 has 20 divisors (see below), whose sum is σ = 32176804. Its totient is φ = 13600224.

The previous prime is 20969989. The next prime is 20970011. The reversal of 20970009 is 90007902.

It can be written as a sum of positive squares in 2 ways, for example, as 13286025 + 7683984 = 3645^2 + 2772^2 .

It is not a de Polignac number, because 20970009 - 2⁷ = 20969881 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20970049) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 502 + ... + 6495.

Almost surely, 2^20970009 is an apocalyptic number.

It is an amenable number.

20970009 is a deficient number, since it is larger than the sum of its proper divisors (11206795).

20970009 is an equidigital number, since it uses as much as digits as its factorization.

20970009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7046 (or 7037 counting only the distinct ones).

The product of its (nonzero) digits is 1134, while the sum is 27.

The square root of 20970009 is about 4579.3022394247. The cubic root of 20970009 is about 275.7610171368.

The spelling of 20970009 in words is "twenty million, nine hundred seventy thousand, nine".