21530645 has 8 divisors (see below), whose sum is σ = 26960256. Its totient is φ = 16475536.

The previous prime is 21530627. The next prime is 21530669. The reversal of 21530645 is 54603512.

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 21530645 - 2⁸ = 21530389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93497 + ... + 93726.

It is an arithmetic number, because the mean of its divisors is an integer number (3370032).

Almost surely, 2^21530645 is an apocalyptic number.

It is an amenable number.

21530645 is a deficient number, since it is larger than the sum of its proper divisors (5429611).

21530645 is a wasteful number, since it uses less digits than its factorization.

21530645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187251.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21530645 is about 4640.1126063922. The cubic root of 21530645 is about 278.1969387617.

The spelling of 21530645 in words is "twenty-one million, five hundred thirty thousand, six hundred forty-five".