65644991999 has 4 divisors (see below), whose sum is σ = 65705384064. Its totient is φ = 65584599936.

The previous prime is 65644991983. The next prime is 65644992103. The reversal of 65644991999 is 99919944656.

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 65644991999 - 2⁴ = 65644991983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65644999999) 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, 30194402 + ... + 30196575.

It is an arithmetic number, because the mean of its divisors is an integer number (16426346016).

Almost surely, 2^65644991999 is an apocalyptic number.

65644991999 is a deficient number, since it is larger than the sum of its proper divisors (60392065).

65644991999 is a wasteful number, since it uses less digits than its factorization.

65644991999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60392064.

The product of its digits is 170061120, while the sum is 71.

The spelling of 65644991999 in words is "sixty-five billion, six hundred forty-four million, nine hundred ninety-one thousand, nine hundred ninety-nine".