21339366399 has 48 divisors (see below), whose sum is σ = 35202533184. Its totient is φ = 12339993600.

The previous prime is 21339366383. The next prime is 21339366401. The reversal of 21339366399 is 99366393312.

It is a happy number.

21339366399 is a `hidden beast` number, since 213 + 3 + 9 + 36 + 6 + 399 = 666.

It is a Cunningham number, because it is equal to 146080²-1.

It is not a de Polignac number, because 21339366399 - 2⁴ = 21339366383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21339366359) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1306614 + ... + 1322844.

It is an arithmetic number, because the mean of its divisors is an integer number (733386108).

Almost surely, 2^21339366399 is an apocalyptic number.

21339366399 is a deficient number, since it is larger than the sum of its proper divisors (13863166785).

21339366399 is a wasteful number, since it uses less digits than its factorization.

21339366399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16928 (or 16925 counting only the distinct ones).

The product of its digits is 4251528, while the sum is 54.

The spelling of 21339366399 in words is "twenty-one billion, three hundred thirty-nine million, three hundred sixty-six thousand, three hundred ninety-nine".