667491660 has 216 divisors, whose sum is σ = 2344109040. Its totient is φ = 153204480.

The previous prime is 667491647. The next prime is 667491673. The reversal of 667491660 is 66194766.

It is a happy number.

667491660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (667491647) and next prime (667491673).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 413014 + ... + 414626.

Almost surely, 2^667491660 is an apocalyptic number.

667491660 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 667491660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1172054520).

667491660 is an abundant number, since it is smaller than the sum of its proper divisors (1676617380).

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

667491660 is a wasteful number, since it uses less digits than its factorization.

667491660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1669 (or 1653 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The square root of 667491660 is about 25835.8599624630. The cubic root of 667491660 is about 873.9406652254.

The spelling of 667491660 in words is "six hundred sixty-seven million, four hundred ninety-one thousand, six hundred sixty".