21664435443413 has 16 divisors (see below), whose sum is σ = 24872070925440. Its totient is φ = 18485139568896.

The previous prime is 21664435443401. The next prime is 21664435443419. The reversal of 21664435443413 is 31434453446612.

It is not a de Polignac number, because 21664435443413 - 2²⁸ = 21664167007957 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 (21664435443419) 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, 5070920 + ... + 8309217.

It is an arithmetic number, because the mean of its divisors is an integer number (1554504432840).

Almost surely, 2^{21664435443413} is an apocalyptic number.

It is an amenable number.

21664435443413 is a deficient number, since it is larger than the sum of its proper divisors (3207635482027).

21664435443413 is a wasteful number, since it uses less digits than its factorization.

21664435443413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13381196.

The product of its digits is 9953280, while the sum is 50.

The spelling of 21664435443413 in words is "twenty-one trillion, six hundred sixty-four billion, four hundred thirty-five million, four hundred forty-three thousand, four hundred thirteen".