66894640 has 20 divisors (see below), whose sum is σ = 155530224. Its totient is φ = 26757824.

The previous prime is 66894629. The next prime is 66894671. The reversal of 66894640 is 4649866.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 418012 + ... + 418171.

Almost surely, 2^66894640 is an apocalyptic number.

It is an amenable number.

66894640 is an abundant number, since it is smaller than the sum of its proper divisors (88635584).

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

66894640 is a wasteful number, since it uses less digits than its factorization.

66894640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836196 (or 836190 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 43.

The square root of 66894640 is about 8178.9143533846. The cubic root of 66894640 is about 405.9418004858.

The spelling of 66894640 in words is "sixty-six million, eight hundred ninety-four thousand, six hundred forty".