12815859421 has 4 divisors (see below), whose sum is σ = 12817340032. Its totient is φ = 12814378812.

The previous prime is 12815859401. The next prime is 12815859431. The reversal of 12815859421 is 12495851821.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12495851821 = 18097 ⋅690493.

It is a cyclic number.

It is not a de Polignac number, because 12815859421 - 2²⁹ = 12278988509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12815859401) 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, 727245 + ... + 744658.

It is an arithmetic number, because the mean of its divisors is an integer number (3204335008).

Almost surely, 2^12815859421 is an apocalyptic number.

It is an amenable number.

12815859421 is a deficient number, since it is larger than the sum of its proper divisors (1480611).

12815859421 is an equidigital number, since it uses as much as digits as its factorization.

12815859421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1480610.

The product of its digits is 230400, while the sum is 46.

The spelling of 12815859421 in words is "twelve billion, eight hundred fifteen million, eight hundred fifty-nine thousand, four hundred twenty-one".