21630680 has 32 divisors (see below), whose sum is σ = 48803040. Its totient is φ = 8628480.

The previous prime is 21630659. The next prime is 21630689. The reversal of 21630680 is 8603612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24812 + ... + 25668.

It is an arithmetic number, because the mean of its divisors is an integer number (1525095).

Almost surely, 2^21630680 is an apocalyptic number.

21630680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21630680 is an abundant number, since it is smaller than the sum of its proper divisors (27172360).

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

21630680 is a wasteful number, since it uses less digits than its factorization.

21630680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1499 (or 1495 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21630680 is about 4650.8794867208. The cubic root of 21630680 is about 278.6271231431.

The spelling of 21630680 in words is "twenty-one million, six hundred thirty thousand, six hundred eighty".