66666398 has 8 divisors (see below), whose sum is σ = 102127392. Its totient is φ = 32623936.

The previous prime is 66666371. The next prime is 66666409. The reversal of 66666398 is 89366666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354515 + ... + 354702.

It is an arithmetic number, because the mean of its divisors is an integer number (12765924).

Almost surely, 2^66666398 is an apocalyptic number.

66666398 is a deficient number, since it is larger than the sum of its proper divisors (35460994).

66666398 is a wasteful number, since it uses less digits than its factorization.

66666398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709266.

The product of its digits is 1679616, while the sum is 50.

The square root of 66666398 is about 8164.9493568546. The cubic root of 66666398 is about 405.4795883425.

The spelling of 66666398 in words is "sixty-six million, six hundred sixty-six thousand, three hundred ninety-eight".