21724486 has 16 divisors (see below), whose sum is σ = 39202560. Its totient is φ = 8820360.

The previous prime is 21724457. The next prime is 21724499. The reversal of 21724486 is 68442712.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40570 + ... + 41101.

It is an arithmetic number, because the mean of its divisors is an integer number (2450160).

Almost surely, 2^21724486 is an apocalyptic number.

21724486 is a deficient number, since it is larger than the sum of its proper divisors (17478074).

21724486 is a wasteful number, since it uses less digits than its factorization.

21724486 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81699.

The product of its digits is 21504, while the sum is 34.

The square root of 21724486 is about 4660.9533359604. The cubic root of 21724486 is about 279.0293173716.

The spelling of 21724486 in words is "twenty-one million, seven hundred twenty-four thousand, four hundred eighty-six".