12661916391 has 24 divisors (see below), whose sum is σ = 18377523216. Its totient is φ = 8400712320.

The previous prime is 12661916329. The next prime is 12661916411. The reversal of 12661916391 is 19361916621.

12661916391 is a `hidden beast` number, since 1 + 2 + 6 + 6 + 1 + 9 + 1 + 639 + 1 = 666.

It is not a de Polignac number, because 12661916391 - 2⁶ = 12661916327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12661916321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1920721 + ... + 1927301.

It is an arithmetic number, because the mean of its divisors is an integer number (765730134).

Almost surely, 2^12661916391 is an apocalyptic number.

12661916391 is a deficient number, since it is larger than the sum of its proper divisors (5715606825).

12661916391 is a wasteful number, since it uses less digits than its factorization.

12661916391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7583 (or 7580 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The spelling of 12661916391 in words is "twelve billion, six hundred sixty-one million, nine hundred sixteen thousand, three hundred ninety-one".