21630506 has 8 divisors (see below), whose sum is σ = 32516640. Its totient is φ = 10791628.

The previous prime is 21630487. The next prime is 21630517. The reversal of 21630506 is 60503612.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10646 + ... + 12513.

It is an arithmetic number, because the mean of its divisors is an integer number (4064580).

Almost surely, 2^21630506 is an apocalyptic number.

21630506 is a deficient number, since it is larger than the sum of its proper divisors (10886134).

21630506 is a wasteful number, since it uses less digits than its factorization.

21630506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23628.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 21630506 is about 4650.8607805437. The cubic root of 21630506 is about 278.6263760368.

The spelling of 21630506 in words is "twenty-one million, six hundred thirty thousand, five hundred six".