21458447 has 4 divisors (see below), whose sum is σ = 21615216. Its totient is φ = 21301680.

The previous prime is 21458443. The next prime is 21458449. The reversal of 21458447 is 74485412.

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 21458447 - 2² = 21458443 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21458443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78179 + ... + 78452.

It is an arithmetic number, because the mean of its divisors is an integer number (5403804).

Almost surely, 2^21458447 is an apocalyptic number.

21458447 is a deficient number, since it is larger than the sum of its proper divisors (156769).

21458447 is a wasteful number, since it uses less digits than its factorization.

21458447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156768.

The product of its digits is 35840, while the sum is 35.

The square root of 21458447 is about 4632.3263054323. The cubic root of 21458447 is about 277.8856343408.

The spelling of 21458447 in words is "twenty-one million, four hundred fifty-eight thousand, four hundred forty-seven".