21935881 has 8 divisors (see below), whose sum is σ = 24070464. Its totient is φ = 19824720.

The previous prime is 21935869. The next prime is 21935909. The reversal of 21935881 is 18853912.

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 21935881 - 2¹⁵ = 21903113 is a prime.

It is a super-2 number, since 2×21935881² = 962365750492322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21935881.

It is not an unprimeable number, because it can be changed into a prime (21935581) 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 7 ways as a sum of consecutive naturals, for example, 3861 + ... + 7666.

It is an arithmetic number, because the mean of its divisors is an integer number (3008808).

Almost surely, 2^21935881 is an apocalyptic number.

It is an amenable number.

21935881 is a deficient number, since it is larger than the sum of its proper divisors (2134583).

21935881 is a wasteful number, since it uses less digits than its factorization.

21935881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11711.

The product of its digits is 17280, while the sum is 37.

The square root of 21935881 is about 4683.5756639559. The cubic root of 21935881 is about 279.9314500556.

It can be divided in two parts, 219 and 35881, that added together give a square (36100 = 190²).

The spelling of 21935881 in words is "twenty-one million, nine hundred thirty-five thousand, eight hundred eighty-one".