21936275881 has 9 divisors (see below), whose sum is σ = 23755567269. Its totient is φ = 20247092736.

The previous prime is 21936275861. The next prime is 21936275887. The reversal of 21936275881 is 18857263912.

It is a happy number.

The square root of 21936275881 is 148109.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 403648281 + 21532627600 = 20091^2 + 146740^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21936275881 is a prime.

It is a super-2 number, since 2×21936275881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21936275887) 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 8 ways as a sum of consecutive naturals, for example, 1919721 + ... + 1931113.

Almost surely, 2^21936275881 is an apocalyptic number.

21936275881 is the 148109-th square number.

21936275881 is the 74055-th centered octagonal number.

It is an amenable number.

21936275881 is a deficient number, since it is larger than the sum of its proper divisors (1819291388).

21936275881 is an frugal number, since it uses more digits than its factorization.

21936275881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22812 (or 11406 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 52.

The spelling of 21936275881 in words is "twenty-one billion, nine hundred thirty-six million, two hundred seventy-five thousand, eight hundred eighty-one".