21225079 has 4 divisors (see below), whose sum is σ = 21234384. Its totient is φ = 21215776.

The previous prime is 21225077. The next prime is 21225097. The reversal of 21225079 is 97052212.

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 21225079 - 2¹ = 21225077 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 (21225077) 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, 1359 + ... + 6655.

It is an arithmetic number, because the mean of its divisors is an integer number (5308596).

Almost surely, 2^21225079 is an apocalyptic number.

21225079 is a deficient number, since it is larger than the sum of its proper divisors (9305).

21225079 is an equidigital number, since it uses as much as digits as its factorization.

21225079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9304.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21225079 is about 4607.0683737058. The cubic root of 21225079 is about 276.8745929740.

The spelling of 21225079 in words is "twenty-one million, two hundred twenty-five thousand, seventy-nine".