8157056991391 has 64 divisors (see below), whose sum is σ = 10336037031936. Its totient is φ = 6252966547200.

The previous prime is 8157056991383. The next prime is 8157056991463. The reversal of 8157056991391 is 1931996507518.

It is a cyclic number.

It is not a de Polignac number, because 8157056991391 - 2³ = 8157056991383 is a prime.

It is a super-2 number, since 2×8157056991391² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8157056991491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3788692371 + ... + 3788694523.

It is an arithmetic number, because the mean of its divisors is an integer number (161500578624).

Almost surely, 2^{8157056991391} is an apocalyptic number.

8157056991391 is a deficient number, since it is larger than the sum of its proper divisors (2178980040545).

8157056991391 is a wasteful number, since it uses less digits than its factorization.

8157056991391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4492.

The product of its (nonzero) digits is 18370800, while the sum is 64.

The spelling of 8157056991391 in words is "eight trillion, one hundred fifty-seven billion, fifty-six million, nine hundred ninety-one thousand, three hundred ninety-one".