66938820 has 48 divisors (see below), whose sum is σ = 201848640. Its totient is φ = 16477056.

The previous prime is 66938801. The next prime is 66938821. The reversal of 66938820 is 2883966.

It is not an unprimeable number, because it can be changed into a prime (66938821) 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 15 ways as a sum of consecutive naturals, for example, 42130 + ... + 43689.

It is an arithmetic number, because the mean of its divisors is an integer number (4205180).

Almost surely, 2^66938820 is an apocalyptic number.

66938820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66938820 is an abundant number, since it is smaller than the sum of its proper divisors (134909820).

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

66938820 is a wasteful number, since it uses less digits than its factorization.

66938820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85844 (or 85842 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 66938820 is about 8181.6147550468. The cubic root of 66938820 is about 406.0311477636.

The spelling of 66938820 in words is "sixty-six million, nine hundred thirty-eight thousand, eight hundred twenty".