66889999 has 4 divisors (see below), whose sum is σ = 72970920. Its totient is φ = 60809080.

The previous prime is 66889993. The next prime is 66890017. The reversal of 66889999 is 99998866.

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 66889999 - 2⁷ = 66889871 is a prime.

66889999 is a modest number, since divided by 9999 gives 6688 as remainder.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 66889999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66889993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3040444 + ... + 3040465.

It is an arithmetic number, because the mean of its divisors is an integer number (18242730).

Almost surely, 2^66889999 is an apocalyptic number.

66889999 is a deficient number, since it is larger than the sum of its proper divisors (6080921).

66889999 is a wasteful number, since it uses less digits than its factorization.

66889999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6080920.

The product of its digits is 15116544, while the sum is 64.

The square root of 66889999 is about 8178.6306311020. The cubic root of 66889999 is about 405.9324124916.

The spelling of 66889999 in words is "sixty-six million, eight hundred eighty-nine thousand, nine hundred ninety-nine".