21975653 has 4 divisors (see below), whose sum is σ = 25115040. Its totient is φ = 18836268.

The previous prime is 21975637. The next prime is 21975691. The reversal of 21975653 is 35657912.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21975653 - 2⁴ = 21975637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21975053) 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 3 ways as a sum of consecutive naturals, for example, 1569683 + ... + 1569696.

It is an arithmetic number, because the mean of its divisors is an integer number (6278760).

Almost surely, 2^21975653 is an apocalyptic number.

It is an amenable number.

21975653 is a deficient number, since it is larger than the sum of its proper divisors (3139387).

21975653 is an equidigital number, since it uses as much as digits as its factorization.

21975653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3139386.

The product of its digits is 56700, while the sum is 38.

The square root of 21975653 is about 4687.8196424351. The cubic root of 21975653 is about 280.1005293785.

The spelling of 21975653 in words is "twenty-one million, nine hundred seventy-five thousand, six hundred fifty-three".