21630366 has 12 divisors (see below), whose sum is σ = 46865832. Its totient is φ = 7210116.

The previous prime is 21630359. The next prime is 21630383. The reversal of 21630366 is 66303612.

21630366 is a `hidden beast` number, since 21 + 630 + 3 + 6 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 600826 + ... + 600861.

It is an arithmetic number, because the mean of its divisors is an integer number (3905486).

Almost surely, 2^21630366 is an apocalyptic number.

21630366 is an abundant number, since it is smaller than the sum of its proper divisors (25235466).

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

21630366 is a wasteful number, since it uses less digits than its factorization.

21630366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201695 (or 1201692 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

The square root of 21630366 is about 4650.8457295421. The cubic root of 21630366 is about 278.6257749140.

Adding to 21630366 its reverse (66303612), we get a palindrome (87933978).

The spelling of 21630366 in words is "twenty-one million, six hundred thirty thousand, three hundred sixty-six".