21430579 has 4 divisors (see below), whose sum is σ = 22121920. Its totient is φ = 20739240.

The previous prime is 21430573. The next prime is 21430597. The reversal of 21430579 is 97503412.

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 21430579 - 2³ = 21430571 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 691309 = 21430579 / (2 + 1 + 4 + 3 + 0 + 5 + 7 + 9).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21430579.

It is not an unprimeable number, because it can be changed into a prime (21430571) 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, 345624 + ... + 345685.

It is an arithmetic number, because the mean of its divisors is an integer number (5530480).

Almost surely, 2^21430579 is an apocalyptic number.

21430579 is a deficient number, since it is larger than the sum of its proper divisors (691341).

21430579 is an equidigital number, since it uses as much as digits as its factorization.

21430579 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691340.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21430579 is about 4629.3173362819. The cubic root of 21430579 is about 277.7652859034.

The spelling of 21430579 in words is "twenty-one million, four hundred thirty thousand, five hundred seventy-nine".