65999999 has 8 divisors (see below), whose sum is σ = 72418752. Its totient is φ = 59772960.

The previous prime is 65999993. The next prime is 66000007. The reversal of 65999999 is 99999956.

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

It is not a de Polignac number, because 65999999 - 2²⁰ = 64951423 is a prime.

It is a Duffinian number.

65999999 is a modest number, since divided by 9999 gives 6599 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65999993) 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, 47207 + ... + 48584.

It is an arithmetic number, because the mean of its divisors is an integer number (9052344).

Almost surely, 2^65999999 is an apocalyptic number.

65999999 is a deficient number, since it is larger than the sum of its proper divisors (6418753).

65999999 is a wasteful number, since it uses less digits than its factorization.

65999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95857.

The product of its digits is 15943230, while the sum is 65.

The square root of 65999999 is about 8124.0383430902. The cubic root of 65999999 is about 404.1240000212.

The spelling of 65999999 in words is "sixty-five million, nine hundred ninety-nine thousand, nine hundred ninety-nine".