21613678439 has 4 divisors (see below), whose sum is σ = 21704112480. Its totient is φ = 21523244400.

The previous prime is 21613678421. The next prime is 21613678469. The reversal of 21613678439 is 93487631612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21613678439 - 2⁸ = 21613678183 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 (21613678469) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45216662 + ... + 45217139.

It is an arithmetic number, because the mean of its divisors is an integer number (5426028120).

Almost surely, 2^21613678439 is an apocalyptic number.

21613678439 is a deficient number, since it is larger than the sum of its proper divisors (90434041).

21613678439 is an equidigital number, since it uses as much as digits as its factorization.

21613678439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90434040.

The product of its digits is 1306368, while the sum is 50.

The spelling of 21613678439 in words is "twenty-one billion, six hundred thirteen million, six hundred seventy-eight thousand, four hundred thirty-nine".