66899999 has 2 divisors, whose sum is σ = 66900000. Its totient is φ = 66899998.

The previous prime is 66899983. The next prime is 66900017. The reversal of 66899999 is 99999866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66899999 - 2⁴ = 66899983 is a prime.

It is a Chen prime.

66899999 is a modest number, since divided by 9999 gives 6689 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66892999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33449999 + 33450000.

It is an arithmetic number, because the mean of its divisors is an integer number (33450000).

Almost surely, 2^66899999 is an apocalyptic number.

66899999 is a deficient number, since it is larger than the sum of its proper divisors (1).

66899999 is an equidigital number, since it uses as much as digits as its factorization.

66899999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17006112, while the sum is 65.

The square root of 66899999 is about 8179.2419575411. The cubic root of 66899999 is about 405.9526403379.

The spelling of 66899999 in words is "sixty-six million, eight hundred ninety-nine thousand, nine hundred ninety-nine".