21666030 has 32 divisors (see below), whose sum is σ = 52157088. Its totient is φ = 5760000.

The previous prime is 21666019. The next prime is 21666037. The reversal of 21666030 is 3066612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21666037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11130 + ... + 12930.

It is an arithmetic number, because the mean of its divisors is an integer number (1629909).

Almost surely, 2^21666030 is an apocalyptic number.

21666030 is an abundant number, since it is smaller than the sum of its proper divisors (30491058).

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

21666030 is a wasteful number, since it uses less digits than its factorization.

21666030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2212.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 21666030 is about 4654.6782917834. The cubic root of 21666030 is about 278.7788229227.

The spelling of 21666030 in words is "twenty-one million, six hundred sixty-six thousand, thirty".