66207820 has 36 divisors (see below), whose sum is σ = 161738640. Its totient is φ = 22699488.

The previous prime is 66207811. The next prime is 66207821. The reversal of 66207820 is 2870266.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66207821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32800 + ... + 34759.

It is an arithmetic number, because the mean of its divisors is an integer number (4492740).

Almost surely, 2^66207820 is an apocalyptic number.

It is an amenable number.

66207820 is an abundant number, since it is smaller than the sum of its proper divisors (95530820).

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

66207820 is a wasteful number, since it uses less digits than its factorization.

66207820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67582 (or 67573 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 66207820 is about 8136.8187886913. The cubic root of 66207820 is about 404.5477245553.

The spelling of 66207820 in words is "sixty-six million, two hundred seven thousand, eight hundred twenty".