21956767873 has 4 divisors (see below), whose sum is σ = 22203473220. Its totient is φ = 21710062528.

The previous prime is 21956767853. The next prime is 21956767879. The reversal of 21956767873 is 37876765912.

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 10702316304 + 11254451569 = 103452^2 + 106087^2 .

It is a cyclic number.

It is not a de Polignac number, because 21956767873 - 2³³ = 13366833281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21956767879) 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, 123352540 + ... + 123352717.

It is an arithmetic number, because the mean of its divisors is an integer number (5550868305).

Almost surely, 2^21956767873 is an apocalyptic number.

It is an amenable number.

21956767873 is a deficient number, since it is larger than the sum of its proper divisors (246705347).

21956767873 is an equidigital number, since it uses as much as digits as its factorization.

21956767873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246705346.

The product of its digits is 26671680, while the sum is 61.

The spelling of 21956767873 in words is "twenty-one billion, nine hundred fifty-six million, seven hundred sixty-seven thousand, eight hundred seventy-three".