66820140 has 84 divisors (see below), whose sum is σ = 210433104. Its totient is φ = 17814816.

The previous prime is 66820123. The next prime is 66820153. The reversal of 66820140 is 4102866.

It is a super-2 number, since 2×66820140² = 8929862219239200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 12289 + ... + 16871.

It is an arithmetic number, because the mean of its divisors is an integer number (2505156).

Almost surely, 2^66820140 is an apocalyptic number.

66820140 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 66820140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105216552).

66820140 is an abundant number, since it is smaller than the sum of its proper divisors (143612964).

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

66820140 is a wasteful number, since it uses less digits than its factorization.

66820140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4610 (or 4593 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 66820140 is about 8174.3586904417. The cubic root of 66820140 is about 405.7910465136.

The spelling of 66820140 in words is "sixty-six million, eight hundred twenty thousand, one hundred forty".