66021660 has 36 divisors (see below), whose sum is σ = 200266248. Its totient is φ = 17605728.

The previous prime is 66021647. The next prime is 66021667. The reversal of 66021660 is 6612066.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-3 number, since 3×66021660³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66021667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 183214 + ... + 183573.

Almost surely, 2^66021660 is an apocalyptic number.

66021660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66021660 is an abundant number, since it is smaller than the sum of its proper divisors (134244588).

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

66021660 is a wasteful number, since it uses less digits than its factorization.

66021660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366802 (or 366797 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 66021660 is about 8125.3713761280. The cubic root of 66021660 is about 404.1682059435.

The spelling of 66021660 in words is "sixty-six million, twenty-one thousand, six hundred sixty".