21925881 has 6 divisors (see below), whose sum is σ = 31670730. Its totient is φ = 14617248.

The previous prime is 21925879. The next prime is 21925907. The reversal of 21925881 is 18852912.

It can be written as a sum of positive squares in only one way, i.e., 14175225 + 7750656 = 3765^2 + 2784^2 .

It is not a de Polignac number, because 21925881 - 2¹ = 21925879 is a prime.

It is a super-2 number, since 2×21925881² = 961488515252322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21925481) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1218096 + ... + 1218113.

It is an arithmetic number, because the mean of its divisors is an integer number (5278455).

Almost surely, 2^21925881 is an apocalyptic number.

It is an amenable number.

21925881 is a deficient number, since it is larger than the sum of its proper divisors (9744849).

21925881 is a wasteful number, since it uses less digits than its factorization.

21925881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2436215 (or 2436212 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21925881 is about 4682.5079818405. The cubic root of 21925881 is about 279.8889057574. Note that the first 3 decimals are identical.

The spelling of 21925881 in words is "twenty-one million, nine hundred twenty-five thousand, eight hundred eighty-one".