66670640 has 40 divisors (see below), whose sum is σ = 158622288. Its totient is φ = 26046720.

The previous prime is 66670631. The next prime is 66670657. The reversal of 66670640 is 4607666.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 66670640.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6251 + ... + 13130.

Almost surely, 2^66670640 is an apocalyptic number.

It is an amenable number.

66670640 is an abundant number, since it is smaller than the sum of its proper divisors (91951648).

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

66670640 is a wasteful number, since it uses less digits than its factorization.

66670640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19437 (or 19431 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 66670640 is about 8165.2091216331. The cubic root of 66670640 is about 405.4881884168.

The spelling of 66670640 in words is "sixty-six million, six hundred seventy thousand, six hundred forty".