21675630 has 16 divisors (see below), whose sum is σ = 52021584. Its totient is φ = 5780160.

The previous prime is 21675613. The next prime is 21675649. The reversal of 21675630 is 3657612.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 722521 = 21675630 / (2 + 1 + 6 + 7 + 5 + 6 + 3 + 0).

It is a Curzon 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, 361231 + ... + 361290.

It is an arithmetic number, because the mean of its divisors is an integer number (3251349).

Almost surely, 2^21675630 is an apocalyptic number.

21675630 is an abundant number, since it is smaller than the sum of its proper divisors (30345954).

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

21675630 is a wasteful number, since it uses less digits than its factorization.

21675630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722531.

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 21675630 is about 4655.7093981476. The cubic root of 21675630 is about 278.8199915404.

The spelling of 21675630 in words is "twenty-one million, six hundred seventy-five thousand, six hundred thirty".