66398818 has 8 divisors (see below), whose sum is σ = 99829548. Its totient is φ = 33122304.

The previous prime is 66398747. The next prime is 66398819. The reversal of 66398818 is 81889366.

It can be written as a sum of positive squares in 2 ways, for example, as 51165409 + 15233409 = 7153^2 + 3903^2 .

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

It is not an unprimeable number, because it can be changed into a prime (66398819) 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, 37471 + ... + 39202.

Almost surely, 2^66398818 is an apocalyptic number.

66398818 is a deficient number, since it is larger than the sum of its proper divisors (33430730).

66398818 is a wasteful number, since it uses less digits than its factorization.

66398818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77108.

The product of its digits is 497664, while the sum is 49.

The square root of 66398818 is about 8148.5469870401. The cubic root of 66398818 is about 404.9363675875.

The spelling of 66398818 in words is "sixty-six million, three hundred ninety-eight thousand, eight hundred eighteen".