21085653 has 8 divisors (see below), whose sum is σ = 28470400. Its totient is φ = 13879008.

The previous prime is 21085643. The next prime is 21085703. The reversal of 21085653 is 35658012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21085653 - 2⁵ = 21085621 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 21085653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44248 + ... + 44721.

It is an arithmetic number, because the mean of its divisors is an integer number (3558800).

Almost surely, 2^21085653 is an apocalyptic number.

It is an amenable number.

21085653 is a deficient number, since it is larger than the sum of its proper divisors (7384747).

21085653 is an equidigital number, since it uses as much as digits as its factorization.

21085653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89051.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 21085653 is about 4591.9116934018. The cubic root of 21085653 is about 276.2670042699.

The spelling of 21085653 in words is "twenty-one million, eighty-five thousand, six hundred fifty-three".