66999799 has 8 divisors (see below), whose sum is σ = 68141168. Its totient is φ = 65862720.

The previous prime is 66999797. The next prime is 66999853. The reversal of 66999799 is 99799966.

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

It is a cyclic number.

It is not a de Polignac number, because 66999799 - 2¹ = 66999797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66999799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66999797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50059 + ... + 51379.

It is an arithmetic number, because the mean of its divisors is an integer number (8517646).

Almost surely, 2^66999799 is an apocalyptic number.

66999799 is a deficient number, since it is larger than the sum of its proper divisors (1141369).

66999799 is a wasteful number, since it uses less digits than its factorization.

66999799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2145.

The product of its digits is 14880348, while the sum is 64.

The square root of 66999799 is about 8185.3404938341. The cubic root of 66999799 is about 406.1544038894.

The spelling of 66999799 in words is "sixty-six million, nine hundred ninety-nine thousand, seven hundred ninety-nine".