20807213 has 12 divisors (see below), whose sum is σ = 24797052. Its totient is φ = 17398080.

The previous prime is 20807191. The next prime is 20807219. The reversal of 20807213 is 31270802.

It can be written as a sum of positive squares in 2 ways, for example, as 4831204 + 15976009 = 2198^2 + 3997^2 .

It is not a de Polignac number, because 20807213 - 2¹⁰ = 20806189 is a prime.

It is a super-2 number, since 2×20807213² = 865880225654738, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20807219) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3170 + ... + 7187.

It is an arithmetic number, because the mean of its divisors is an integer number (2066421).

Almost surely, 2^20807213 is an apocalyptic number.

It is an amenable number.

20807213 is a deficient number, since it is larger than the sum of its proper divisors (3989839).

20807213 is a wasteful number, since it uses less digits than its factorization.

20807213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10412 (or 10405 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 20807213 is about 4561.4924092889. The cubic root of 20807213 is about 275.0455593939.

The spelling of 20807213 in words is "twenty million, eight hundred seven thousand, two hundred thirteen".