1256921105163 has 24 divisors (see below), whose sum is σ = 1788597017280. Its totient is φ = 782970131520.

The previous prime is 1256921105107. The next prime is 1256921105171. The reversal of 1256921105163 is 3615011296521.

It is not a de Polignac number, because 1256921105163 - 2⁹ = 1256921104651 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1256921105963) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1765233 + ... + 2372738.

It is an arithmetic number, because the mean of its divisors is an integer number (74524875720).

Almost surely, 2^{1256921105163} is an apocalyptic number.

1256921105163 is a deficient number, since it is larger than the sum of its proper divisors (531675912117).

1256921105163 is an equidigital number, since it uses as much as digits as its factorization.

1256921105163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4138139 (or 4138066 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 42.

The spelling of 1256921105163 in words is "one trillion, two hundred fifty-six billion, nine hundred twenty-one million, one hundred five thousand, one hundred sixty-three".