21247726 has 8 divisors (see below), whose sum is σ = 31936464. Its totient is φ = 10602240.

The previous prime is 21247693. The next prime is 21247727. The reversal of 21247726 is 62774212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21247727) 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 3 ways as a sum of consecutive naturals, for example, 9555 + ... + 11566.

It is an arithmetic number, because the mean of its divisors is an integer number (3992058).

Almost surely, 2^21247726 is an apocalyptic number.

21247726 is a deficient number, since it is larger than the sum of its proper divisors (10688738).

21247726 is a wasteful number, since it uses less digits than its factorization.

21247726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21626.

The product of its digits is 9408, while the sum is 31.

The square root of 21247726 is about 4609.5255721169. The cubic root of 21247726 is about 276.9730323418.

The spelling of 21247726 in words is "twenty-one million, two hundred forty-seven thousand, seven hundred twenty-six".