20321399 has 16 divisors (see below), whose sum is σ = 24631296. Its totient is φ = 16394400.

The previous prime is 20321387. The next prime is 20321401. The reversal of 20321399 is 99312302.

It is a cyclic number.

It is not a de Polignac number, because 20321399 - 2²⁰ = 19272823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20321339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6764 + ... + 9294.

It is an arithmetic number, because the mean of its divisors is an integer number (1539456).

Almost surely, 2^20321399 is an apocalyptic number.

20321399 is a deficient number, since it is larger than the sum of its proper divisors (4309897).

20321399 is a wasteful number, since it uses less digits than its factorization.

20321399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2606.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 20321399 is about 4507.9262416326. The cubic root of 20321399 is about 272.8880603028. Note that the first 3 decimals are identical.

The spelling of 20321399 in words is "twenty million, three hundred twenty-one thousand, three hundred ninety-nine".