21552653 has 2 divisors, whose sum is σ = 21552654. Its totient is φ = 21552652.

The previous prime is 21552637. The next prime is 21552659. The reversal of 21552653 is 35625512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21548164 + 4489 = 4642^2 + 67^2 .

It is a cyclic number.

It is not a de Polignac number, because 21552653 - 2⁴ = 21552637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21552659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10776326 + 10776327.

It is an arithmetic number, because the mean of its divisors is an integer number (10776327).

Almost surely, 2^21552653 is an apocalyptic number.

It is an amenable number.

21552653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21552653 is an equidigital number, since it uses as much as digits as its factorization.

21552653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9000, while the sum is 29.

The square root of 21552653 is about 4642.4834948549. The cubic root of 21552653 is about 278.2916947604.

The spelling of 21552653 in words is "twenty-one million, five hundred fifty-two thousand, six hundred fifty-three".