666181580 has 24 divisors (see below), whose sum is σ = 1400707728. Its totient is φ = 266143808.

The previous prime is 666181577. The next prime is 666181583. The reversal of 666181580 is 85181666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (666181577) and next prime (666181583).

It is not an unprimeable number, because it can be changed into a prime (666181583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3599 + ... + 36678.

It is an arithmetic number, because the mean of its divisors is an integer number (58362822).

Almost surely, 2^666181580 is an apocalyptic number.

It is an amenable number.

666181580 is an abundant number, since it is smaller than the sum of its proper divisors (734526148).

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

666181580 is a wasteful number, since it uses less digits than its factorization.

666181580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41113 (or 41111 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 41.

The square root of 666181580 is about 25810.4936024091. The cubic root of 666181580 is about 873.3685322073.

The spelling of 666181580 in words is "six hundred sixty-six million, one hundred eighty-one thousand, five hundred eighty".