21275888181 has 4 divisors (see below), whose sum is σ = 28367850912. Its totient is φ = 14183925452.

The previous prime is 21275888047. The next prime is 21275888197. The reversal of 21275888181 is 18188857212.

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 21275888181 - 2²⁷ = 21141670453 is a prime.

It is a super-2 number, since 2×21275888181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275788181) 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, 3545981361 + ... + 3545981366.

It is an arithmetic number, because the mean of its divisors is an integer number (7091962728).

Almost surely, 2^21275888181 is an apocalyptic number.

It is an amenable number.

21275888181 is a deficient number, since it is larger than the sum of its proper divisors (7091962731).

21275888181 is an equidigital number, since it uses as much as digits as its factorization.

21275888181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7091962730.

The product of its digits is 573440, while the sum is 51.

The spelling of 21275888181 in words is "twenty-one billion, two hundred seventy-five million, eight hundred eighty-eight thousand, one hundred eighty-one".