21266331399 has 24 divisors (see below), whose sum is σ = 31118822592. Its totient is φ = 13993620480.

The previous prime is 21266331389. The next prime is 21266331431. The reversal of 21266331399 is 99313366212.

21266331399 is a `hidden beast` number, since 2 + 1 + 2 + 6 + 633 + 1 + 3 + 9 + 9 = 666.

It is not a de Polignac number, because 21266331399 - 2¹⁶ = 21266265863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266331329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 201714 + ... + 288480.

It is an arithmetic number, because the mean of its divisors is an integer number (1296617608).

Almost surely, 2^21266331399 is an apocalyptic number.

21266331399 is a deficient number, since it is larger than the sum of its proper divisors (9852491193).

21266331399 is a wasteful number, since it uses less digits than its factorization.

21266331399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87127 (or 87124 counting only the distinct ones).

The product of its digits is 314928, while the sum is 45.

The spelling of 21266331399 in words is "twenty-one billion, two hundred sixty-six million, three hundred thirty-one thousand, three hundred ninety-nine".