21630600 has 144 divisors (see below), whose sum is σ = 74208420. Its totient is φ = 5644800.

The previous prime is 21630593. The next prime is 21630601. The reversal of 21630600 is 603612.

It is a happy number.

21630600 is a `hidden beast` number, since 2 + 1 + 63 + 0 + 600 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 8191044 + 13439556 = 2862^2 + 3666^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21630601) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 109702 + ... + 109898.

Almost surely, 2^21630600 is an apocalyptic number.

21630600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21630600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37104210).

21630600 is an abundant number, since it is smaller than the sum of its proper divisors (52577820).

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

21630600 is a wasteful number, since it uses less digits than its factorization.

21630600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21630600 is about 4650.8708861890. The cubic root of 21630600 is about 278.6267796465.

The spelling of 21630600 in words is "twenty-one million, six hundred thirty thousand, six hundred".