21881292161 has 8 divisors (see below), whose sum is σ = 23194740744. Its totient is φ = 20570767360.

The previous prime is 21881292151. The next prime is 21881292197. The reversal of 21881292161 is 16129218812.

It can be written as a sum of positive squares in 4 ways, for example, as 5975290000 + 15906002161 = 77300^2 + 126119^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21881292161 - 2¹⁴ = 21881275777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21881292151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 715520 + ... + 745473.

It is an arithmetic number, because the mean of its divisors is an integer number (2899342593).

Almost surely, 2^21881292161 is an apocalyptic number.

It is an amenable number.

21881292161 is a deficient number, since it is larger than the sum of its proper divisors (1313448583).

21881292161 is a wasteful number, since it uses less digits than its factorization.

21881292161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461891.

The product of its digits is 27648, while the sum is 41.

The spelling of 21881292161 in words is "twenty-one billion, eight hundred eighty-one million, two hundred ninety-two thousand, one hundred sixty-one".