12905840639 has 4 divisors (see below), whose sum is σ = 12915761880. Its totient is φ = 12895919400.

The previous prime is 12905840603. The next prime is 12905840669. The reversal of 12905840639 is 93604850921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93604850921 = 23 ⋅4069776127.

It is a cyclic number.

It is not a de Polignac number, because 12905840639 - 2¹² = 12905836543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12905840593 and 12905840602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12905840669) 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, 4958669 + ... + 4961270.

It is an arithmetic number, because the mean of its divisors is an integer number (3228940470).

Almost surely, 2^12905840639 is an apocalyptic number.

12905840639 is a deficient number, since it is larger than the sum of its proper divisors (9921241).

12905840639 is an equidigital number, since it uses as much as digits as its factorization.

12905840639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9921240.

The product of its (nonzero) digits is 466560, while the sum is 47.

The spelling of 12905840639 in words is "twelve billion, nine hundred five million, eight hundred forty thousand, six hundred thirty-nine".