21724677 has 12 divisors (see below), whose sum is σ = 33794124. Its totient is φ = 13368960.

The previous prime is 21724663. The next prime is 21724721. The reversal of 21724677 is 77642712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9235521 + 12489156 = 3039^2 + 3534^2 .

It is not a de Polignac number, because 21724677 - 2⁶ = 21724613 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21724607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92724 + ... + 92957.

It is an arithmetic number, because the mean of its divisors is an integer number (2816177).

Almost surely, 2^21724677 is an apocalyptic number.

It is an amenable number.

21724677 is a deficient number, since it is larger than the sum of its proper divisors (12069447).

21724677 is a wasteful number, since it uses less digits than its factorization.

21724677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185700 (or 185697 counting only the distinct ones).

The product of its digits is 32928, while the sum is 36.

The square root of 21724677 is about 4660.9738252859. The cubic root of 21724677 is about 279.0301351039.

The spelling of 21724677 in words is "twenty-one million, seven hundred twenty-four thousand, six hundred seventy-seven".