21224479 has 2 divisors, whose sum is σ = 21224480. Its totient is φ = 21224478.

The previous prime is 21224447. The next prime is 21224503. The reversal of 21224479 is 97442212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21224479 - 2⁵ = 21224447 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21224479.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21224579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612239 + 10612240.

It is an arithmetic number, because the mean of its divisors is an integer number (10612240).

Almost surely, 2^21224479 is an apocalyptic number.

21224479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224479 is an equidigital number, since it uses as much as digits as its factorization.

21224479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 31.

The square root of 21224479 is about 4607.0032559138. The cubic root of 21224479 is about 276.8719840112.

The spelling of 21224479 in words is "twenty-one million, two hundred twenty-four thousand, four hundred seventy-nine".