21673626413 has 4 divisors (see below), whose sum is σ = 21673944348. Its totient is φ = 21673308480.

The previous prime is 21673626397. The next prime is 21673626421. The reversal of 21673626413 is 31462637612.

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 9646775524 + 12026850889 = 98218^2 + 109667^2 .

It is a cyclic number.

It is not a de Polignac number, because 21673626413 - 2⁴ = 21673626397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21673626433) 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, 10478 + ... + 208463.

It is an arithmetic number, because the mean of its divisors is an integer number (5418486087).

Almost surely, 2^21673626413 is an apocalyptic number.

It is an amenable number.

21673626413 is a deficient number, since it is larger than the sum of its proper divisors (317935).

21673626413 is an equidigital number, since it uses as much as digits as its factorization.

21673626413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317934.

The product of its digits is 217728, while the sum is 41.

The spelling of 21673626413 in words is "twenty-one billion, six hundred seventy-three million, six hundred twenty-six thousand, four hundred thirteen".