66681340018 has 8 divisors (see below), whose sum is σ = 100027253340. Its totient is φ = 33338922240.

The previous prime is 66681339961. The next prime is 66681340021. The reversal of 66681340018 is 81004318666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 66410836209 + 270503809 = 257703^2 + 16447^2 .

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

It is a super-2 number, since 2×66681340018² (a number of 22 digits) contains 22 as substring.

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, 825663 + ... + 902818.

Almost surely, 2^66681340018 is an apocalyptic number.

66681340018 is a deficient number, since it is larger than the sum of its proper divisors (33345913322).

66681340018 is a wasteful number, since it uses less digits than its factorization.

66681340018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1747772.

The product of its (nonzero) digits is 165888, while the sum is 43.

The spelling of 66681340018 in words is "sixty-six billion, six hundred eighty-one million, three hundred forty thousand, eighteen".