21403579 has 2 divisors, whose sum is σ = 21403580. Its totient is φ = 21403578.

The previous prime is 21403559. The next prime is 21403621. The reversal of 21403579 is 97530412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21403579 - 2¹¹ = 21401531 is a prime.

It is a super-2 number, since 2×21403579² = 916226388018482, which contains 22 as substring.

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 21403579.

It is not a weakly prime, because it can be changed into another prime (21403559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701789 + 10701790.

It is an arithmetic number, because the mean of its divisors is an integer number (10701790).

Almost surely, 2^21403579 is an apocalyptic number.

21403579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403579 is an equidigital number, since it uses as much as digits as its factorization.

21403579 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21403579 is about 4626.4002204738. The cubic root of 21403579 is about 277.6485863890.

The spelling of 21403579 in words is "twenty-one million, four hundred three thousand, five hundred seventy-nine".