20723399 has 2 divisors, whose sum is σ = 20723400. Its totient is φ = 20723398.

The previous prime is 20723393. The next prime is 20723401. The reversal of 20723399 is 99332702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20723399 - 2²⁴ = 3946183 is a prime.

It is a super-2 number, since 2×20723399² = 858918532226402, which contains 22 as substring.

Together with 20723401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20723393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10361699 + 10361700.

It is an arithmetic number, because the mean of its divisors is an integer number (10361700).

Almost surely, 2^20723399 is an apocalyptic number.

20723399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20723399 is an equidigital number, since it uses as much as digits as its factorization.

20723399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 35.

The square root of 20723399 is about 4552.2960141010. The cubic root of 20723399 is about 274.6757566888.

The spelling of 20723399 in words is "twenty million, seven hundred twenty-three thousand, three hundred ninety-nine".