66118660 has 48 divisors (see below), whose sum is σ = 146442240. Its totient is φ = 25038720.

The previous prime is 66118621. The next prime is 66118699. The reversal of 66118660 is 6681166.

66118660 = 1163² + 1164² + ... + 1209².

It is an interprime number because it is at equal distance from previous prime (66118621) and next prime (66118699).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28006 + ... + 30274.

It is an arithmetic number, because the mean of its divisors is an integer number (3050880).

Almost surely, 2^66118660 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 66118660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73221120).

66118660 is an abundant number, since it is smaller than the sum of its proper divisors (80323580).

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

66118660 is a wasteful number, since it uses less digits than its factorization.

66118660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2356 (or 2354 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 66118660 is about 8131.3381432578. The cubic root of 66118660 is about 404.3660457221.

It can be divided in two parts, 661 and 18660, that added together give a square (19321 = 139²).

The spelling of 66118660 in words is "sixty-six million, one hundred eighteen thousand, six hundred sixty".