21066988 has 12 divisors (see below), whose sum is σ = 38470320. Its totient is φ = 10075472.

The previous prime is 21066973. The next prime is 21067003. The reversal of 21066988 is 88966012.

It is an interprime number because it is at equal distance from previous prime (21066973) and next prime (21067003).

It is a self number, because there is not a number n which added to its sum of digits gives 21066988.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114403 + ... + 114586.

It is an arithmetic number, because the mean of its divisors is an integer number (3205860).

Almost surely, 2^21066988 is an apocalyptic number.

It is an amenable number.

21066988 is a deficient number, since it is larger than the sum of its proper divisors (17403332).

21066988 is a wasteful number, since it uses less digits than its factorization.

21066988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229016 (or 229014 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 21066988 is about 4589.8788655040. The cubic root of 21066988 is about 276.1854631085.

The spelling of 21066988 in words is "twenty-one million, sixty-six thousand, nine hundred eighty-eight".