21985092913 has 4 divisors (see below), whose sum is σ = 25125820480. Its totient is φ = 18844365348.

The previous prime is 21985092893. The next prime is 21985092929. The reversal of 21985092913 is 31929058912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21985092913 - 2⁵ = 21985092881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21985692913) 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, 1570363773 + ... + 1570363786.

It is an arithmetic number, because the mean of its divisors is an integer number (6281455120).

Almost surely, 2^21985092913 is an apocalyptic number.

It is an amenable number.

21985092913 is a deficient number, since it is larger than the sum of its proper divisors (3140727567).

21985092913 is an equidigital number, since it uses as much as digits as its factorization.

21985092913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3140727566.

The product of its (nonzero) digits is 349920, while the sum is 49.

The spelling of 21985092913 in words is "twenty-one billion, nine hundred eighty-five million, ninety-two thousand, nine hundred thirteen".