21605714 has 8 divisors (see below), whose sum is σ = 34901580. Its totient is φ = 9971856.

The previous prime is 21605711. The next prime is 21605747. The reversal of 21605714 is 41750612.

It can be written as a sum of positive squares in 2 ways, for example, as 20857489 + 748225 = 4567^2 + 865^2 .

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

It is a Harshad number since it is a multiple of its sum of digits (26), and also a Moran number because the ratio is a prime number: 830989 = 21605714 / (2 + 1 + 6 + 0 + 5 + 7 + 1 + 4).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21605711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 415469 + ... + 415520.

Almost surely, 2^21605714 is an apocalyptic number.

21605714 is a deficient number, since it is larger than the sum of its proper divisors (13295866).

21605714 is a wasteful number, since it uses less digits than its factorization.

21605714 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831004.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21605714 is about 4648.1947033230. The cubic root of 21605714 is about 278.5198852948.

The spelling of 21605714 in words is "twenty-one million, six hundred five thousand, seven hundred fourteen".