21817623955 has 16 divisors (see below), whose sum is σ = 26751957120. Its totient is φ = 17073942912.

The previous prime is 21817623923. The next prime is 21817623977. The reversal of 21817623955 is 55932671812.

It is a cyclic number.

It is not a de Polignac number, because 21817623955 - 2⁵ = 21817623923 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21817623899 and 21817623908.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 453937 + ... + 499693.

It is an arithmetic number, because the mean of its divisors is an integer number (1671997320).

Almost surely, 2^21817623955 is an apocalyptic number.

21817623955 is a deficient number, since it is larger than the sum of its proper divisors (4934333165).

21817623955 is a wasteful number, since it uses less digits than its factorization.

21817623955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47838.

The product of its digits is 907200, while the sum is 49.

The spelling of 21817623955 in words is "twenty-one billion, eight hundred seventeen million, six hundred twenty-three thousand, nine hundred fifty-five".