21877691813 has 4 divisors (see below), whose sum is σ = 21880261248. Its totient is φ = 21875122380.

The previous prime is 21877691807. The next prime is 21877691831. The reversal of 21877691813 is 31819677812.

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 21877691813 - 2⁶ = 21877691749 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 (21877691863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1271903 + ... + 1288988.

It is an arithmetic number, because the mean of its divisors is an integer number (5470065312).

Almost surely, 2^21877691813 is an apocalyptic number.

It is an amenable number.

21877691813 is a deficient number, since it is larger than the sum of its proper divisors (2569435).

21877691813 is an equidigital number, since it uses as much as digits as its factorization.

21877691813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2569434.

The product of its digits is 1016064, while the sum is 53.

The spelling of 21877691813 in words is "twenty-one billion, eight hundred seventy-seven million, six hundred ninety-one thousand, eight hundred thirteen".