21066900 has 36 divisors (see below), whose sum is σ = 60954432. Its totient is φ = 5617760.

The previous prime is 21066863. The next prime is 21066931. The reversal of 21066900 is 966012.

It is a super-4 number, since 4×21066900⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34812 + ... + 35411.

Almost surely, 2^21066900 is an apocalyptic number.

21066900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21066900 is an abundant number, since it is smaller than the sum of its proper divisors (39887532).

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

21066900 is a wasteful number, since it uses less digits than its factorization.

21066900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70240 (or 70233 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21066900 is about 4589.8692791843. The cubic root of 21066900 is about 276.1850785518.

The spelling of 21066900 in words is "twenty-one million, sixty-six thousand, nine hundred".