21715726 has 16 divisors (see below), whose sum is σ = 34097184. Its totient is φ = 10353024.

The previous prime is 21715723. The next prime is 21715741. The reversal of 21715726 is 62751712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715721) 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 7 ways as a sum of consecutive naturals, for example, 20506 + ... + 21538.

It is an arithmetic number, because the mean of its divisors is an integer number (2131074).

Almost surely, 2^21715726 is an apocalyptic number.

21715726 is a deficient number, since it is larger than the sum of its proper divisors (12381458).

21715726 is a wasteful number, since it uses less digits than its factorization.

21715726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515.

The product of its digits is 5880, while the sum is 31.

The square root of 21715726 is about 4660.0135192937. The cubic root of 21715726 is about 278.9918078469.

The spelling of 21715726 in words is "twenty-one million, seven hundred fifteen thousand, seven hundred twenty-six".