66405398 has 4 divisors (see below), whose sum is σ = 99608100. Its totient is φ = 33202698.

The previous prime is 66405371. The next prime is 66405403. The reversal of 66405398 is 89350466.

66405398 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89350466 = 2 ⋅44675233.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16601348 + ... + 16601351.

It is an arithmetic number, because the mean of its divisors is an integer number (24902025).

Almost surely, 2^66405398 is an apocalyptic number.

66405398 is a deficient number, since it is larger than the sum of its proper divisors (33202702).

66405398 is a wasteful number, since it uses less digits than its factorization.

66405398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33202701.

The product of its (nonzero) digits is 155520, while the sum is 41.

The square root of 66405398 is about 8148.9507300020. The cubic root of 66405398 is about 404.9497432939.

The spelling of 66405398 in words is "sixty-six million, four hundred five thousand, three hundred ninety-eight".