21490717 has 8 divisors (see below), whose sum is σ = 22579200. Its totient is φ = 20415120.

The previous prime is 21490709. The next prime is 21490739. The reversal of 21490717 is 71709412.

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

It is a cyclic number.

It is not a de Polignac number, because 21490717 - 2³ = 21490709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21490757) 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, 292 + ... + 6562.

It is an arithmetic number, because the mean of its divisors is an integer number (2822400).

Almost surely, 2^21490717 is an apocalyptic number.

It is an amenable number.

21490717 is a deficient number, since it is larger than the sum of its proper divisors (1088483).

21490717 is a wasteful number, since it uses less digits than its factorization.

21490717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6443.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 21490717 is about 4635.8081280398. The cubic root of 21490717 is about 278.0248627764.

The spelling of 21490717 in words is "twenty-one million, four hundred ninety thousand, seven hundred seventeen".