66775920 has 40 divisors (see below), whose sum is σ = 207006096. Its totient is φ = 17806848.

The previous prime is 66775913. The next prime is 66775927. The reversal of 66775920 is 2957766.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66775913) and next prime (66775927).

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66775927) 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 7 ways as a sum of consecutive naturals, for example, 138877 + ... + 139356.

Almost surely, 2^66775920 is an apocalyptic number.

66775920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66775920 is an abundant number, since it is smaller than the sum of its proper divisors (140230176).

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

66775920 is a wasteful number, since it uses less digits than its factorization.

66775920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278249 (or 278243 counting only the distinct ones).

The product of its (nonzero) digits is 158760, while the sum is 42.

The square root of 66775920 is about 8171.6534434593. The cubic root of 66775920 is about 405.7015124307.

The spelling of 66775920 in words is "sixty-six million, seven hundred seventy-five thousand, nine hundred twenty".