66823920 has 80 divisors (see below), whose sum is σ = 230178720. Its totient is φ = 17819136.

The previous prime is 66823909. The next prime is 66823949. The reversal of 66823920 is 2932866.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 15 ways as a sum of consecutive naturals, for example, 13309 + ... + 17628.

It is an arithmetic number, because the mean of its divisors is an integer number (2877234).

Almost surely, 2^66823920 is an apocalyptic number.

66823920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66823920 is an abundant number, since it is smaller than the sum of its proper divisors (163354800).

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

66823920 is a wasteful number, since it uses less digits than its factorization.

66823920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30959 (or 30947 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 66823920 is about 8174.5898979704. The cubic root of 66823920 is about 405.7986982048.

The spelling of 66823920 in words is "sixty-six million, eight hundred twenty-three thousand, nine hundred twenty".