21379893 has 4 divisors (see below), whose sum is σ = 28506528. Its totient is φ = 14253260.

The previous prime is 21379879. The next prime is 21379907. The reversal of 21379893 is 39897312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21379879) and next prime (21379907).

It is a cyclic number.

It is not a de Polignac number, because 21379893 - 2¹² = 21375797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21379823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3563313 + ... + 3563318.

It is an arithmetic number, because the mean of its divisors is an integer number (7126632).

Almost surely, 2^21379893 is an apocalyptic number.

It is an amenable number.

21379893 is a deficient number, since it is larger than the sum of its proper divisors (7126635).

21379893 is an equidigital number, since it uses as much as digits as its factorization.

21379893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7126634.

The product of its digits is 81648, while the sum is 42.

The square root of 21379893 is about 4623.8396382228. The cubic root of 21379893 is about 277.5461298201.

The spelling of 21379893 in words is "twenty-one million, three hundred seventy-nine thousand, eight hundred ninety-three".