12985916781 has 4 divisors (see below), whose sum is σ = 17314555712. Its totient is φ = 8657277852.

The previous prime is 12985916777. The next prime is 12985916791. The reversal of 12985916781 is 18761958921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 12985916781 - 2² = 12985916777 is a prime.

It is a super-2 number, since 2×12985916781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12985916791) 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, 2164319461 + ... + 2164319466.

It is an arithmetic number, because the mean of its divisors is an integer number (4328638928).

Almost surely, 2^12985916781 is an apocalyptic number.

It is an amenable number.

12985916781 is a deficient number, since it is larger than the sum of its proper divisors (4328638931).

12985916781 is an equidigital number, since it uses as much as digits as its factorization.

12985916781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4328638930.

The product of its digits is 2177280, while the sum is 57.

The spelling of 12985916781 in words is "twelve billion, nine hundred eighty-five million, nine hundred sixteen thousand, seven hundred eighty-one".