21175013 has 4 divisors (see below), whose sum is σ = 22420620. Its totient is φ = 19929408.

The previous prime is 21174977. The next prime is 21175031. The reversal of 21175013 is 31057112.

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 9628609 + 11546404 = 3103^2 + 3398^2 .

It is a cyclic number.

It is not a de Polignac number, because 21175013 - 2¹² = 21170917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21175073) 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, 622778 + ... + 622811.

It is an arithmetic number, because the mean of its divisors is an integer number (5605155).

Almost surely, 2^21175013 is an apocalyptic number.

It is an amenable number.

21175013 is a deficient number, since it is larger than the sum of its proper divisors (1245607).

21175013 is a wasteful number, since it uses less digits than its factorization.

21175013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245606.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21175013 is about 4601.6315584801. The cubic root of 21175013 is about 276.6567230826.

The spelling of 21175013 in words is "twenty-one million, one hundred seventy-five thousand, thirteen".