21628013 has 8 divisors (see below), whose sum is σ = 23638176. Its totient is φ = 19625200.

The previous prime is 21628001. The next prime is 21628021. The reversal of 21628013 is 31082612.

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 21628013 - 2²² = 17433709 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 21628013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621013) 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, 5678 + ... + 8688.

It is an arithmetic number, because the mean of its divisors is an integer number (2954772).

Almost surely, 2^21628013 is an apocalyptic number.

It is an amenable number.

21628013 is a deficient number, since it is larger than the sum of its proper divisors (2010163).

21628013 is a wasteful number, since it uses less digits than its factorization.

21628013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3675.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21628013 is about 4650.5927579181. The cubic root of 21628013 is about 278.6156713675.

The spelling of 21628013 in words is "twenty-one million, six hundred twenty-eight thousand, thirteen".