20813399 has 2 divisors, whose sum is σ = 20813400. Its totient is φ = 20813398.

The previous prime is 20813393. The next prime is 20813447. The reversal of 20813399 is 99331802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20813399 - 2¹² = 20809303 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20813393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10406699 + 10406700.

It is an arithmetic number, because the mean of its divisors is an integer number (10406700).

Almost surely, 2^20813399 is an apocalyptic number.

20813399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20813399 is an equidigital number, since it uses as much as digits as its factorization.

20813399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 20813399 is about 4562.1704264527. The cubic root of 20813399 is about 275.0728137767.

It can be divided in two parts, 20813 and 399, that added together give a palindrome (21212).

The spelling of 20813399 in words is "twenty million, eight hundred thirteen thousand, three hundred ninety-nine".