7891256521987 has 4 divisors (see below), whose sum is σ = 7897312744720. Its totient is φ = 7885200299256.

The previous prime is 7891256521957. The next prime is 7891256521991.

7891256521987 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7891256521987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7891256521957) 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, 3028109412 + ... + 3028112017.

It is an arithmetic number, because the mean of its divisors is an integer number (1974328186180).

Almost surely, 2^{7891256521987} is an apocalyptic number.

7891256521987 is a deficient number, since it is larger than the sum of its proper divisors (6056222733).

7891256521987 is a wasteful number, since it uses less digits than its factorization.

7891256521987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6056222732.

The product of its digits is 152409600, while the sum is 70.

The spelling of 7891256521987 in words is "seven trillion, eight hundred ninety-one billion, two hundred fifty-six million, five hundred twenty-one thousand, nine hundred eighty-seven".