21447459 has 12 divisors (see below), whose sum is σ = 33796152. Its totient is φ = 12998400.

The previous prime is 21447427. The next prime is 21447509. The reversal of 21447459 is 95474412.

It is a happy number.

It is not a de Polignac number, because 21447459 - 2⁵ = 21447427 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21447259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108222 + ... + 108419.

It is an arithmetic number, because the mean of its divisors is an integer number (2816346).

Almost surely, 2^21447459 is an apocalyptic number.

21447459 is a deficient number, since it is larger than the sum of its proper divisors (12348693).

21447459 is a wasteful number, since it uses less digits than its factorization.

21447459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216658 (or 216655 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21447459 is about 4631.1401403974. The cubic root of 21447459 is about 277.8381949234.

The spelling of 21447459 in words is "twenty-one million, four hundred forty-seven thousand, four hundred fifty-nine".