21630768 has 20 divisors (see below), whose sum is σ = 55879608. Its totient is φ = 7210240.

The previous prime is 21630761. The next prime is 21630769. The reversal of 21630768 is 86703612.

It is not an unprimeable number, because it can be changed into a prime (21630761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225273 + ... + 225368.

Almost surely, 2^21630768 is an apocalyptic number.

It is an amenable number.

21630768 is an abundant number, since it is smaller than the sum of its proper divisors (34248840).

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

21630768 is a wasteful number, since it uses less digits than its factorization.

21630768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450652 (or 450646 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21630768 is about 4650.8889472874. Note that the first 3 decimals coincide. The cubic root of 21630768 is about 278.6275009884.

The spelling of 21630768 in words is "twenty-one million, six hundred thirty thousand, seven hundred sixty-eight".