66645890 has 16 divisors (see below), whose sum is σ = 120201408. Its totient is φ = 26605296.

The previous prime is 66645889. The next prime is 66645893. The reversal of 66645890 is 9854666.

It is not an unprimeable number, because it can be changed into a prime (66645893) 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, 1142 + ... + 11601.

It is an arithmetic number, because the mean of its divisors is an integer number (7512588).

Almost surely, 2^66645890 is an apocalyptic number.

66645890 is a deficient number, since it is larger than the sum of its proper divisors (53555518).

66645890 is a wasteful number, since it uses less digits than its factorization.

66645890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13273.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 66645890 is about 8163.6934043361. The cubic root of 66645890 is about 405.4380060338.

The spelling of 66645890 in words is "sixty-six million, six hundred forty-five thousand, eight hundred ninety".