66775320 has 128 divisors (see below), whose sum is σ = 235742400. Its totient is φ = 16754688.

The previous prime is 66775309. The next prime is 66775321. The reversal of 66775320 is 2357766.

It is a happy number.

It is a super-2 number, since 2×66775320² = 8917886722204800, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66775321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16542 + ... + 20178.

Almost surely, 2^66775320 is an apocalyptic number.

66775320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66775320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117871200).

66775320 is an abundant number, since it is smaller than the sum of its proper divisors (168967080).

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

66775320 is a wasteful number, since it uses less digits than its factorization.

66775320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3674 (or 3664 counting only the distinct ones).

The product of its (nonzero) digits is 52920, while the sum is 36.

The square root of 66775320 is about 8171.6167311004. The cubic root of 66775320 is about 405.7002973139.

The spelling of 66775320 in words is "sixty-six million, seven hundred seventy-five thousand, three hundred twenty".