21095213 has 4 divisors (see below), whose sum is σ = 21134748. Its totient is φ = 21055680.

The previous prime is 21095201. The next prime is 21095227. The reversal of 21095213 is 31259012.

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 6980164 + 14115049 = 2642^2 + 3757^2 .

It is a cyclic number.

It is not a de Polignac number, because 21095213 - 2¹⁴ = 21078829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21095293) 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, 18956 + ... + 20037.

It is an arithmetic number, because the mean of its divisors is an integer number (5283687).

Almost surely, 2^21095213 is an apocalyptic number.

It is an amenable number.

21095213 is a deficient number, since it is larger than the sum of its proper divisors (39535).

21095213 is an equidigital number, since it uses as much as digits as its factorization.

21095213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39534.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21095213 is about 4592.9525362233. The cubic root of 21095213 is about 276.3087500881.

The spelling of 21095213 in words is "twenty-one million, ninety-five thousand, two hundred thirteen".