21724474 has 8 divisors (see below), whose sum is σ = 32617728. Its totient is φ = 10851900.

The previous prime is 21724457. The next prime is 21724499. The reversal of 21724474 is 47442712.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2202 + ... + 6949.

It is an arithmetic number, because the mean of its divisors is an integer number (4077216).

Almost surely, 2^21724474 is an apocalyptic number.

21724474 is a deficient number, since it is larger than the sum of its proper divisors (10893254).

21724474 is a wasteful number, since it uses less digits than its factorization.

21724474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10340.

The product of its digits is 12544, while the sum is 31.

The square root of 21724474 is about 4660.9520486699. The cubic root of 21724474 is about 279.0292659956.

The spelling of 21724474 in words is "twenty-one million, seven hundred twenty-four thousand, four hundred seventy-four".