21611453 has 4 divisors (see below), whose sum is σ = 21934080. Its totient is φ = 21288828.

The previous prime is 21611411. The next prime is 21611461. The reversal of 21611453 is 35411612.

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 21611453 - 2⁶ = 21611389 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 (21611353) 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, 161213 + ... + 161346.

It is an arithmetic number, because the mean of its divisors is an integer number (5483520).

Almost surely, 2^21611453 is an apocalyptic number.

It is an amenable number.

21611453 is a deficient number, since it is larger than the sum of its proper divisors (322627).

21611453 is an equidigital number, since it uses as much as digits as its factorization.

21611453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322626.

The product of its digits is 720, while the sum is 23.

The square root of 21611453 is about 4648.8119987799. The cubic root of 21611453 is about 278.5445436501.

The spelling of 21611453 in words is "twenty-one million, six hundred eleven thousand, four hundred fifty-three".