21036605 has 8 divisors (see below), whose sum is σ = 26341632. Its totient is φ = 16097488.

The previous prime is 21036577. The next prime is 21036611. The reversal of 21036605 is 50663012.

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

It is a cyclic number.

It is not a de Polignac number, because 21036605 - 2²⁴ = 4259389 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91349 + ... + 91578.

It is an arithmetic number, because the mean of its divisors is an integer number (3292704).

Almost surely, 2^21036605 is an apocalyptic number.

It is an amenable number.

21036605 is a deficient number, since it is larger than the sum of its proper divisors (5305027).

21036605 is a wasteful number, since it uses less digits than its factorization.

21036605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182955.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 21036605 is about 4586.5678889557. The cubic root of 21036605 is about 276.0526268406.

Adding to 21036605 its reverse (50663012), we get a palindrome (71699617).

The spelling of 21036605 in words is "twenty-one million, thirty-six thousand, six hundred five".