21670459 has 4 divisors (see below), whose sum is σ = 21885120. Its totient is φ = 21455800.

The previous prime is 21670447. The next prime is 21670477. The reversal of 21670459 is 95407612.

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 21670459 - 2⁷ = 21670331 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21670489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107179 + ... + 107380.

It is an arithmetic number, because the mean of its divisors is an integer number (5471280).

Almost surely, 2^21670459 is an apocalyptic number.

21670459 is a deficient number, since it is larger than the sum of its proper divisors (214661).

21670459 is a wasteful number, since it uses less digits than its factorization.

21670459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214660.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21670459 is about 4655.1540253788. The cubic root of 21670459 is about 278.7978177467.

The spelling of 21670459 in words is "twenty-one million, six hundred seventy thousand, four hundred fifty-nine".