21616653 has 4 divisors (see below), whose sum is σ = 28822208. Its totient is φ = 14411100.

The previous prime is 21616643. The next prime is 21616657. The reversal of 21616653 is 35661612.

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 not a de Polignac number, because 21616653 - 2⁹ = 21616141 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21616653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3602773 + ... + 3602778.

It is an arithmetic number, because the mean of its divisors is an integer number (7205552).

Almost surely, 2^21616653 is an apocalyptic number.

It is an amenable number.

21616653 is a deficient number, since it is larger than the sum of its proper divisors (7205555).

21616653 is an equidigital number, since it uses as much as digits as its factorization.

21616653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7205554.

The product of its digits is 6480, while the sum is 30.

The square root of 21616653 is about 4649.3712478141. The cubic root of 21616653 is about 278.5668823528.

The spelling of 21616653 in words is "twenty-one million, six hundred sixteen thousand, six hundred fifty-three".