21366459 has 6 divisors (see below), whose sum is σ = 30862676. Its totient is φ = 14244300.

The previous prime is 21366407. The next prime is 21366463. The reversal of 21366459 is 95466312.

It is a happy number.

21366459 is a `hidden beast` number, since 2 + 1 + 3 + 6 + 645 + 9 = 666.

It is not a de Polignac number, because 21366459 - 2⁹ = 21365947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21366259) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1187017 + ... + 1187034.

Almost surely, 2^21366459 is an apocalyptic number.

21366459 is a deficient number, since it is larger than the sum of its proper divisors (9496217).

21366459 is a wasteful number, since it uses less digits than its factorization.

21366459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2374057 (or 2374054 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21366459 is about 4622.3867211647. The cubic root of 21366459 is about 277.4879858446.

The spelling of 21366459 in words is "twenty-one million, three hundred sixty-six thousand, four hundred fifty-nine".