66845389 has 4 divisors (see below), whose sum is σ = 71987356. Its totient is φ = 61703424.

The previous prime is 66845369. The next prime is 66845399. The reversal of 66845389 is 98354866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98354866 = 2 ⋅49177433.

It can be written as a sum of positive squares in 2 ways, for example, as 3515625 + 63329764 = 1875^2 + 7958^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66845389 is a prime.

It is a super-2 number, since 2×66845389² = 8936612061122642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66845369) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2570964 + ... + 2570989.

It is an arithmetic number, because the mean of its divisors is an integer number (17996839).

Almost surely, 2^66845389 is an apocalyptic number.

It is an amenable number.

66845389 is a deficient number, since it is larger than the sum of its proper divisors (5141967).

66845389 is a wasteful number, since it uses less digits than its factorization.

66845389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5141966.

The product of its digits is 1244160, while the sum is 49.

The square root of 66845389 is about 8175.9029470756. The cubic root of 66845389 is about 405.8421515043.

The spelling of 66845389 in words is "sixty-six million, eight hundred forty-five thousand, three hundred eighty-nine".