21945459 has 8 divisors (see below), whose sum is σ = 29471680. Its totient is φ = 14524776.

The previous prime is 21945439. The next prime is 21945481. The reversal of 21945459 is 95454912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-21945459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21945409) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25897 + ... + 26730.

It is an arithmetic number, because the mean of its divisors is an integer number (3683960).

Almost surely, 2^21945459 is an apocalyptic number.

21945459 is a deficient number, since it is larger than the sum of its proper divisors (7526221).

21945459 is a wasteful number, since it uses less digits than its factorization.

21945459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52769.

The product of its digits is 64800, while the sum is 39.

The square root of 21945459 is about 4684.5980617338. The cubic root of 21945459 is about 279.9721868632.

The spelling of 21945459 in words is "twenty-one million, nine hundred forty-five thousand, four hundred fifty-nine".