21879640623 has 4 divisors (see below), whose sum is σ = 29172854168. Its totient is φ = 14586427080.

The previous prime is 21879640597. The next prime is 21879640631. The reversal of 21879640623 is 32604697812.

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

It is not a de Polignac number, because 21879640623 - 2¹³ = 21879632431 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 (21879640423) 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, 3646606768 + ... + 3646606773.

It is an arithmetic number, because the mean of its divisors is an integer number (7293213542).

Almost surely, 2^21879640623 is an apocalyptic number.

21879640623 is a deficient number, since it is larger than the sum of its proper divisors (7293213545).

21879640623 is an equidigital number, since it uses as much as digits as its factorization.

21879640623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7293213544.

The product of its (nonzero) digits is 870912, while the sum is 48.

The spelling of 21879640623 in words is "twenty-one billion, eight hundred seventy-nine million, six hundred forty thousand, six hundred twenty-three".