21224379 has 16 divisors (see below), whose sum is σ = 30971520. Its totient is φ = 12821760.

The previous prime is 21224353. The next prime is 21224389. The reversal of 21224379 is 97342212.

It is not a de Polignac number, because 21224379 - 2⁸ = 21224123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21224389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11659 + ... + 13355.

It is an arithmetic number, because the mean of its divisors is an integer number (1935720).

Almost surely, 2^21224379 is an apocalyptic number.

21224379 is a deficient number, since it is larger than the sum of its proper divisors (9747141).

21224379 is a wasteful number, since it uses less digits than its factorization.

21224379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2090.

The product of its digits is 6048, while the sum is 30.

The square root of 21224379 is about 4606.9924028589. The cubic root of 21224379 is about 276.8715491793.

The spelling of 21224379 in words is "twenty-one million, two hundred twenty-four thousand, three hundred seventy-nine".