66387860 has 72 divisors (see below), whose sum is σ = 175176960. Its totient is φ = 20687040.

The previous prime is 66387857. The next prime is 66387883. The reversal of 66387860 is 6878366.

It is a Harshad number since it is a multiple of its sum of digits (44).

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, 14981 + ... + 18899.

Almost surely, 2^66387860 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66387860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87588480).

66387860 is an abundant number, since it is smaller than the sum of its proper divisors (108789100).

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

66387860 is a wasteful number, since it uses less digits than its factorization.

66387860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3957 (or 3944 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 66387860 is about 8147.8745694813. The cubic root of 66387860 is about 404.9140903996.

The spelling of 66387860 in words is "sixty-six million, three hundred eighty-seven thousand, eight hundred sixty".