21238079 has 4 divisors (see below), whose sum is σ = 21247776. Its totient is φ = 21228384.

The previous prime is 21238073. The next prime is 21238093. The reversal of 21238079 is 97083212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21238079 - 2¹² = 21233983 is a prime.

It is a super-2 number, since 2×21238079² = 902111999220482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21238073) 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, 167 + ... + 6519.

It is an arithmetic number, because the mean of its divisors is an integer number (5311944).

Almost surely, 2^21238079 is an apocalyptic number.

21238079 is a deficient number, since it is larger than the sum of its proper divisors (9697).

21238079 is an equidigital number, since it uses as much as digits as its factorization.

21238079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9696.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21238079 is about 4608.4790332603. The cubic root of 21238079 is about 276.9311084308.

The spelling of 21238079 in words is "twenty-one million, two hundred thirty-eight thousand, seventy-nine".