66391560 has 96 divisors (see below), whose sum is σ = 217002240. Its totient is φ = 17603712.

The previous prime is 66391541. The next prime is 66391583. The reversal of 66391560 is 6519366.

66391560 is a `hidden beast` number, since 6 + 6 + 3 + 91 + 560 = 666.

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 polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 79867 + ... + 80693.

It is an arithmetic number, because the mean of its divisors is an integer number (2260440).

Almost surely, 2^66391560 is an apocalyptic number.

66391560 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 66391560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108501120).

66391560 is an abundant number, since it is smaller than the sum of its proper divisors (150610680).

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

66391560 is a wasteful number, since it uses less digits than its factorization.

66391560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1060 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 36.

The square root of 66391560 is about 8148.1016193958. The cubic root of 66391560 is about 404.9216126298.

The spelling of 66391560 in words is "sixty-six million, three hundred ninety-one thousand, five hundred sixty".