66820820 has 24 divisors (see below), whose sum is σ = 153080928. Its totient is φ = 24298400.

The previous prime is 66820811. The next prime is 66820847. The reversal of 66820820 is 2802866.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 151646 + ... + 152085.

It is an arithmetic number, because the mean of its divisors is an integer number (6378372).

Almost surely, 2^66820820 is an apocalyptic number.

It is an amenable number.

66820820 is an abundant number, since it is smaller than the sum of its proper divisors (86260108).

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

66820820 is a wasteful number, since it uses less digits than its factorization.

66820820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303751 (or 303749 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 66820820 is about 8174.4002838129. The cubic root of 66820820 is about 405.7924230296.

The spelling of 66820820 in words is "sixty-six million, eight hundred twenty thousand, eight hundred twenty".