21918583639291 has 16 divisors (see below), whose sum is σ = 22281636263040. Its totient is φ = 21559288458240.

The previous prime is 21918583639219. The next prime is 21918583639321. The reversal of 21918583639291 is 19293638581912.

It is a cyclic number.

It is not a de Polignac number, because 21918583639291 - 2¹⁷ = 21918583508219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21918583619291) 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, 5676475 + ... + 8721211.

It is an arithmetic number, because the mean of its divisors is an integer number (1392602266440).

Almost surely, 2^{21918583639291} is an apocalyptic number.

21918583639291 is a deficient number, since it is larger than the sum of its proper divisors (363052623749).

21918583639291 is a wasteful number, since it uses less digits than its factorization.

21918583639291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3045354.

The product of its digits is 50388480, while the sum is 67.

The spelling of 21918583639291 in words is "twenty-one trillion, nine hundred eighteen billion, five hundred eighty-three million, six hundred thirty-nine thousand, two hundred ninety-one".