21715710 has 16 divisors (see below), whose sum is σ = 52117776. Its totient is φ = 5790848.

The previous prime is 21715709. The next prime is 21715711. The reversal of 21715710 is 1751712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21715709) and next prime (21715711).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 361899 + ... + 361958.

It is an arithmetic number, because the mean of its divisors is an integer number (3257361).

Almost surely, 2^21715710 is an apocalyptic number.

21715710 is an abundant number, since it is smaller than the sum of its proper divisors (30402066).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21715710 is a wasteful number, since it uses less digits than its factorization.

21715710 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723867.

The product of its (nonzero) digits is 490, while the sum is 24.

The square root of 21715710 is about 4660.0118025602. The cubic root of 21715710 is about 278.9917393271.

The spelling of 21715710 in words is "twenty-one million, seven hundred fifteen thousand, seven hundred ten".