21015179399 has 16 divisors (see below), whose sum is σ = 21455834400. Its totient is φ = 20580397056.

The previous prime is 21015179351. The next prime is 21015179401. The reversal of 21015179399 is 99397151012.

It is a cyclic number.

It is not a de Polignac number, because 21015179399 - 2²⁸ = 20746743943 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 (21015179099) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3527207 + ... + 3533159.

It is an arithmetic number, because the mean of its divisors is an integer number (1340989650).

Almost surely, 2^21015179399 is an apocalyptic number.

21015179399 is a deficient number, since it is larger than the sum of its proper divisors (440655001).

21015179399 is a wasteful number, since it uses less digits than its factorization.

21015179399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6434.

The product of its (nonzero) digits is 153090, while the sum is 47.

The spelling of 21015179399 in words is "twenty-one billion, fifteen million, one hundred seventy-nine thousand, three hundred ninety-nine".