12640279987 has 4 divisors (see below), whose sum is σ = 12765431376. Its totient is φ = 12515128600.

The previous prime is 12640279973. The next prime is 12640279999. The reversal of 12640279987 is 78997204621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78997204621 = 12119 ⋅6518459.

It is a cyclic number.

It is not a de Polignac number, because 12640279987 - 2⁷ = 12640279859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12640279937) 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, 62575543 + ... + 62575744.

It is an arithmetic number, because the mean of its divisors is an integer number (3191357844).

Almost surely, 2^12640279987 is an apocalyptic number.

12640279987 is a deficient number, since it is larger than the sum of its proper divisors (125151389).

12640279987 is a wasteful number, since it uses less digits than its factorization.

12640279987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125151388.

The product of its (nonzero) digits is 3048192, while the sum is 55.

The spelling of 12640279987 in words is "twelve billion, six hundred forty million, two hundred seventy-nine thousand, nine hundred eighty-seven".