21634413613 has 4 divisors (see below), whose sum is σ = 21634775548. Its totient is φ = 21634051680.

The previous prime is 21634413589. The next prime is 21634413667. The reversal of 21634413613 is 31631443612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16989036964 + 4645376649 = 130342^2 + 68157^2 .

It is a cyclic number.

It is not a de Polignac number, because 21634413613 - 2¹⁷ = 21634282541 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 (21634413683) 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, 67656 + ... + 218737.

It is an arithmetic number, because the mean of its divisors is an integer number (5408693887).

Almost surely, 2^21634413613 is an apocalyptic number.

It is an amenable number.

21634413613 is a deficient number, since it is larger than the sum of its proper divisors (361935).

21634413613 is an equidigital number, since it uses as much as digits as its factorization.

21634413613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361934.

The product of its digits is 31104, while the sum is 34.

The spelling of 21634413613 in words is "twenty-one billion, six hundred thirty-four million, four hundred thirteen thousand, six hundred thirteen".