21153776191 has 4 divisors (see below), whose sum is σ = 21158065872. Its totient is φ = 21149486512.

The previous prime is 21153776173. The next prime is 21153776233. The reversal of 21153776191 is 19167735112.

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

It is a cyclic number.

It is not a de Polignac number, because 21153776191 - 2¹¹ = 21153774143 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 (21153773191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137435 + ... + 2147308.

It is an arithmetic number, because the mean of its divisors is an integer number (5289516468).

Almost surely, 2^21153776191 is an apocalyptic number.

21153776191 is a deficient number, since it is larger than the sum of its proper divisors (4289681).

21153776191 is an equidigital number, since it uses as much as digits as its factorization.

21153776191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4289680.

The product of its digits is 79380, while the sum is 43.

The spelling of 21153776191 in words is "twenty-one billion, one hundred fifty-three million, seven hundred seventy-six thousand, one hundred ninety-one".