66015864 has 64 divisors (see below), whose sum is σ = 189312000. Its totient is φ = 21293280.

The previous prime is 66015857. The next prime is 66015869. The reversal of 66015864 is 46851066.

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 (66015869) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1767 + ... + 11625.

It is an arithmetic number, because the mean of its divisors is an integer number (2958000).

Almost surely, 2^66015864 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 66015864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94656000).

66015864 is an abundant number, since it is smaller than the sum of its proper divisors (123296136).

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

66015864 is a wasteful number, since it uses less digits than its factorization.

66015864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9905 (or 9895 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 66015864 is about 8125.0147076790. The cubic root of 66015864 is about 404.1563783732.

The spelling of 66015864 in words is "sixty-six million, fifteen thousand, eight hundred sixty-four".