66069999 has 14 divisors (see below), whose sum is σ = 99060776. Its totient is φ = 44046180.

The previous prime is 66069989. The next prime is 66070009. The reversal of 66069999 is 99996066.

It is an interprime number because it is at equal distance from previous prime (66069989) and next prime (66070009).

It is not a de Polignac number, because 66069999 - 2⁵ = 66069967 is a prime.

It is a Duffinian number.

66069999 is a modest number, since divided by 9999 gives 6606 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66069919) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 44587 + ... + 46044.

Almost surely, 2^66069999 is an apocalyptic number.

66069999 is a deficient number, since it is larger than the sum of its proper divisors (32990777).

66069999 is an frugal number, since it uses more digits than its factorization.

66069999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90649 (or 90634 counting only the distinct ones).

The product of its (nonzero) digits is 1417176, while the sum is 54.

The square root of 66069999 is about 8128.3454035861. The cubic root of 66069999 is about 404.2668216640.

The spelling of 66069999 in words is "sixty-six million, sixty-nine thousand, nine hundred ninety-nine".