66021900 has 144 divisors (see below), whose sum is σ = 220819200. Its totient is φ = 14918400.

The previous prime is 66021877. The next prime is 66021911. The reversal of 66021900 is 912066.

It is a super-2 number, since 2×66021900² = 8717782559220000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 312795 + ... + 313005.

Almost surely, 2^66021900 is an apocalyptic number.

66021900 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66021900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110409600).

66021900 is an abundant number, since it is smaller than the sum of its proper divisors (154797300).

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

66021900 is a wasteful number, since it uses less digits than its factorization.

66021900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384 (or 377 counting only the distinct ones).

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

The square root of 66021900 is about 8125.3861446703. The cubic root of 66021900 is about 404.1686956831.

Adding to 66021900 its reverse (912066), we get a palindrome (66933966).

The spelling of 66021900 in words is "sixty-six million, twenty-one thousand, nine hundred".