66991619896 has 16 divisors (see below), whose sum is σ = 125655867000. Its totient is φ = 33483388704.

The previous prime is 66991619887. The next prime is 66991619899. The reversal of 66991619896 is 69891619966.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66991619899) 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, 1529715 + ... + 1572898.

Almost surely, 2^66991619896 is an apocalyptic number.

It is an amenable number.

66991619896 is a deficient number, since it is larger than the sum of its proper divisors (58664247104).

66991619896 is a wasteful number, since it uses less digits than its factorization.

66991619896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3105318 (or 3105314 counting only the distinct ones).

The product of its digits is 68024448, while the sum is 70.

Adding to 66991619896 its sum of digits (70), we get a palindrome (66991619966).

The spelling of 66991619896 in words is "sixty-six billion, nine hundred ninety-one million, six hundred nineteen thousand, eight hundred ninety-six".