21171326499 has 12 divisors (see below), whose sum is σ = 32379676056. Its totient is φ = 13283969472.

The previous prime is 21171326471. The next prime is 21171326521. The reversal of 21171326499 is 99462317112.

21171326499 is a `hidden beast` number, since 21 + 1 + 7 + 132 + 6 + 499 = 666.

It is not a de Polignac number, because 21171326499 - 2⁸ = 21171326243 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21171326459) 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 11 ways as a sum of consecutive naturals, for example, 69187189 + ... + 69187494.

It is an arithmetic number, because the mean of its divisors is an integer number (2698306338).

Almost surely, 2^21171326499 is an apocalyptic number.

21171326499 is a deficient number, since it is larger than the sum of its proper divisors (11208349557).

21171326499 is a wasteful number, since it uses less digits than its factorization.

21171326499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138374706 (or 138374703 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The spelling of 21171326499 in words is "twenty-one billion, one hundred seventy-one million, three hundred twenty-six thousand, four hundred ninety-nine".