21610013 has 4 divisors (see below), whose sum is σ = 21808380. Its totient is φ = 21411648.

The previous prime is 21610003. The next prime is 21610019. The reversal of 21610013 is 31001612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12687844 + 8922169 = 3562^2 + 2987^2 .

It is a cyclic number.

It is not a de Polignac number, because 21610013 - 2²⁴ = 4832797 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 21610013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21610019) 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, 99020 + ... + 99237.

It is an arithmetic number, because the mean of its divisors is an integer number (5452095).

Almost surely, 2^21610013 is an apocalyptic number.

It is an amenable number.

21610013 is a deficient number, since it is larger than the sum of its proper divisors (198367).

21610013 is a wasteful number, since it uses less digits than its factorization.

21610013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198366.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 21610013 is about 4648.6571179213. The cubic root of 21610013 is about 278.5383569142.

Adding to 21610013 its reverse (31001612), we get a palindrome (52611625).

The spelling of 21610013 in words is "twenty-one million, six hundred ten thousand, thirteen".