666640040 has 64 divisors (see below), whose sum is σ = 1732570560. Its totient is φ = 228152320.

The previous prime is 666640031. The next prime is 666640043. The reversal of 666640040 is 40046666.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 666639979 and 666640006.

It is not an unprimeable number, because it can be changed into a prime (666640043) 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, 37082 + ... + 52041.

It is an arithmetic number, because the mean of its divisors is an integer number (27071415).

Almost surely, 2^666640040 is an apocalyptic number.

It is an amenable number.

666640040 is an abundant number, since it is smaller than the sum of its proper divisors (1065930520).

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

666640040 is a wasteful number, since it uses less digits than its factorization.

666640040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89162 (or 89158 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 666640040 is about 25819.3733463847. The cubic root of 666640040 is about 873.5688343135.

The spelling of 666640040 in words is "six hundred sixty-six million, six hundred forty thousand, forty".