21890653 has 4 divisors (see below), whose sum is σ = 21900348. Its totient is φ = 21880960.

The previous prime is 21890651. The next prime is 21890677. The reversal of 21890653 is 35609812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 16216729 + 5673924 = 4027^2 + 2382^2 .

It is a cyclic number.

It is not a de Polignac number, because 21890653 - 2¹ = 21890651 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 (21890651) 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, 525 + ... + 6637.

It is an arithmetic number, because the mean of its divisors is an integer number (5475087).

Almost surely, 2^21890653 is an apocalyptic number.

It is an amenable number.

21890653 is a deficient number, since it is larger than the sum of its proper divisors (9695).

21890653 is an equidigital number, since it uses as much as digits as its factorization.

21890653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9694.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21890653 is about 4678.7448103097. The cubic root of 21890653 is about 279.7389275697.

The spelling of 21890653 in words is "twenty-one million, eight hundred ninety thousand, six hundred fifty-three".