21813383873 has 12 divisors (see below), whose sum is σ = 22482234684. Its totient is φ = 21163478400.

The previous prime is 21813383863. The next prime is 21813383881. The reversal of 21813383873 is 37838331812.

It can be written as a sum of positive squares in 6 ways, for example, as 16794086464 + 5019297409 = 129592^2 + 70847^2 .

It is not a de Polignac number, because 21813383873 - 2²⁶ = 21746275009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21813383863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 268415 + ... + 340107.

It is an arithmetic number, because the mean of its divisors is an integer number (1873519557).

Almost surely, 2^21813383873 is an apocalyptic number.

It is an amenable number.

21813383873 is a deficient number, since it is larger than the sum of its proper divisors (668850811).

21813383873 is an equidigital number, since it uses as much as digits as its factorization.

21813383873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71956 (or 71915 counting only the distinct ones).

The product of its digits is 580608, while the sum is 47.

The spelling of 21813383873 in words is "twenty-one billion, eight hundred thirteen million, three hundred eighty-three thousand, eight hundred seventy-three".