20809930 has 16 divisors (see below), whose sum is σ = 37521000. Its totient is φ = 8309952.

The previous prime is 20809913. The next prime is 20809931. The reversal of 20809930 is 3990802.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13771521 + 7038409 = 3711^2 + 2653^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20809892 and 20809901.

It is not an unprimeable number, because it can be changed into a prime (20809931) 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, 6196 + ... + 8944.

Almost surely, 2^20809930 is an apocalyptic number.

20809930 is a deficient number, since it is larger than the sum of its proper divisors (16711070).

20809930 is a wasteful number, since it uses less digits than its factorization.

20809930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3513.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 20809930 is about 4561.7902187628. The cubic root of 20809930 is about 275.0575306633.

The spelling of 20809930 in words is "twenty million, eight hundred nine thousand, nine hundred thirty".