66649445 has 4 divisors (see below), whose sum is σ = 79979340. Its totient is φ = 53319552.

The previous prime is 66649439. The next prime is 66649459. The reversal of 66649445 is 54494666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25715041 + 40934404 = 5071^2 + 6398^2 .

It is a cyclic number.

It is not a de Polignac number, because 66649445 - 2⁶ = 66649381 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66649396 and 66649405.

It is a congruent number.

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, 6664940 + ... + 6664949.

It is an arithmetic number, because the mean of its divisors is an integer number (19994835).

Almost surely, 2^66649445 is an apocalyptic number.

It is an amenable number.

66649445 is a deficient number, since it is larger than the sum of its proper divisors (13329895).

66649445 is a wasteful number, since it uses less digits than its factorization.

66649445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13329894.

The product of its digits is 622080, while the sum is 44.

The square root of 66649445 is about 8163.9111337643. The cubic root of 66649445 is about 405.4452148128.

The spelling of 66649445 in words is "sixty-six million, six hundred forty-nine thousand, four hundred forty-five".