21067313 has 4 divisors (see below), whose sum is σ = 21159540. Its totient is φ = 20975088.

The previous prime is 21067303. The next prime is 21067331. The reversal of 21067313 is 31376012.

It is a happy number.

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 16711744 + 4355569 = 4088^2 + 2087^2 .

It is a cyclic number.

It is not a de Polignac number, because 21067313 - 2⁴ = 21067297 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21067303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45770 + ... + 46227.

It is an arithmetic number, because the mean of its divisors is an integer number (5289885).

Almost surely, 2^21067313 is an apocalyptic number.

It is an amenable number.

21067313 is a deficient number, since it is larger than the sum of its proper divisors (92227).

21067313 is an equidigital number, since it uses as much as digits as its factorization.

21067313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92226.

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 21067313 is about 4589.9142693519. The cubic root of 21067313 is about 276.1868833371.

The spelling of 21067313 in words is "twenty-one million, sixty-seven thousand, three hundred thirteen".