66697820 has 36 divisors (see below), whose sum is σ = 162935640. Its totient is φ = 22867488.

The previous prime is 66697819. The next prime is 66697823. The reversal of 66697820 is 2879666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66697823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33050 + ... + 35009.

It is an arithmetic number, because the mean of its divisors is an integer number (4525990).

Almost surely, 2^66697820 is an apocalyptic number.

It is an amenable number.

66697820 is an abundant number, since it is smaller than the sum of its proper divisors (96237820).

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

66697820 is a wasteful number, since it uses less digits than its factorization.

66697820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68082 (or 68073 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 66697820 is about 8166.8733307184. The cubic root of 66697820 is about 405.5432834912.

The spelling of 66697820 in words is "sixty-six million, six hundred ninety-seven thousand, eight hundred twenty".