21962881 has 4 divisors (see below), whose sum is σ = 22123332. Its totient is φ = 21802432.

The previous prime is 21962851. The next prime is 21962893. The reversal of 21962881 is 18826912.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17297281 + 4665600 = 4159^2 + 2160^2 .

It is a cyclic number.

It is not a de Polignac number, because 21962881 - 2¹¹ = 21960833 is a prime.

It is a super-2 number, since 2×21962881² = 964736283640322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21962881.

It is not an unprimeable number, because it can be changed into a prime (21962851) 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, 80020 + ... + 80293.

It is an arithmetic number, because the mean of its divisors is an integer number (5530833).

Almost surely, 2^21962881 is an apocalyptic number.

It is an amenable number.

21962881 is a deficient number, since it is larger than the sum of its proper divisors (160451).

21962881 is a wasteful number, since it uses less digits than its factorization.

21962881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160450.

The product of its digits is 13824, while the sum is 37.

The square root of 21962881 is about 4686.4571906719. The cubic root of 21962881 is about 280.0462551135.

The spelling of 21962881 in words is "twenty-one million, nine hundred sixty-two thousand, eight hundred eighty-one".