21166311639 has 8 divisors (see below), whose sum is σ = 30787362432. Its totient is φ = 12828067640.

The previous prime is 21166311563. The next prime is 21166311643. The reversal of 21166311639 is 93611366112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21166311639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21166311597 and 21166311606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166311659) 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 7 ways as a sum of consecutive naturals, for example, 320701659 + ... + 320701724.

It is an arithmetic number, because the mean of its divisors is an integer number (3848420304).

Almost surely, 2^21166311639 is an apocalyptic number.

21166311639 is a deficient number, since it is larger than the sum of its proper divisors (9621050793).

21166311639 is a wasteful number, since it uses less digits than its factorization.

21166311639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641403397.

The product of its digits is 34992, while the sum is 39.

The spelling of 21166311639 in words is "twenty-one billion, one hundred sixty-six million, three hundred eleven thousand, six hundred thirty-nine".