21986079 has 4 divisors (see below), whose sum is σ = 29314776. Its totient is φ = 14657384.

The previous prime is 21986077. The next prime is 21986101. The reversal of 21986079 is 97068912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21986079 - 2¹ = 21986077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21986079.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21986077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3664344 + ... + 3664349.

It is an arithmetic number, because the mean of its divisors is an integer number (7328694).

Almost surely, 2^21986079 is an apocalyptic number.

21986079 is a deficient number, since it is larger than the sum of its proper divisors (7328697).

21986079 is an equidigital number, since it uses as much as digits as its factorization.

21986079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7328696.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 21986079 is about 4688.9315414068. The cubic root of 21986079 is about 280.1448187928.

The spelling of 21986079 in words is "twenty-one million, nine hundred eighty-six thousand, seventy-nine".