66681099 has 6 divisors (see below), whose sum is σ = 96317156. Its totient is φ = 44454060.

The previous prime is 66681091. The next prime is 66681107. The reversal of 66681099 is 99018666.

It is an interprime number because it is at equal distance from previous prime (66681091) and next prime (66681107).

It is not a de Polignac number, because 66681099 - 2³ = 66681091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66681091) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3704497 + ... + 3704514.

Almost surely, 2^66681099 is an apocalyptic number.

66681099 is a deficient number, since it is larger than the sum of its proper divisors (29636057).

66681099 is a wasteful number, since it uses less digits than its factorization.

66681099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7409017 (or 7409014 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 66681099 is about 8165.8495577619. The cubic root of 66681099 is about 405.5093910492.

The spelling of 66681099 in words is "sixty-six million, six hundred eighty-one thousand, ninety-nine".