66999995 has 4 divisors (see below), whose sum is σ = 80400000. Its totient is φ = 53599992.

The previous prime is 66999983. The next prime is 66999997. The reversal of 66999995 is 59999966.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66999995 - 2¹⁴ = 66983611 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66999997) by changing a digit.

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, 6699995 + ... + 6700004.

It is an arithmetic number, because the mean of its divisors is an integer number (20100000).

Almost surely, 2^66999995 is an apocalyptic number.

66999995 is a deficient number, since it is larger than the sum of its proper divisors (13400005).

66999995 is a wasteful number, since it uses less digits than its factorization.

66999995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13400004.

The product of its digits is 10628820, while the sum is 62.

The square root of 66999995 is about 8185.3524664488. The cubic root of 66999995 is about 406.1547999412.

The spelling of 66999995 in words is "sixty-six million, nine hundred ninety-nine thousand, nine hundred ninety-five".