8156906397491 has 4 divisors (see below), whose sum is σ = 8157915049872. Its totient is φ = 8155897745112.

The previous prime is 8156906397467. The next prime is 8156906397533. The reversal of 8156906397491 is 1947936096518.

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

It is a cyclic number.

It is not a de Polignac number, because 8156906397491 - 2⁴² = 3758859886387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8156906397191) 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 3 ways as a sum of consecutive naturals, for example, 504314060 + ... + 504330233.

It is an arithmetic number, because the mean of its divisors is an integer number (2039478762468).

Almost surely, 2^{8156906397491} is an apocalyptic number.

8156906397491 is a deficient number, since it is larger than the sum of its proper divisors (1008652381).

8156906397491 is a wasteful number, since it uses less digits than its factorization.

8156906397491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008652380.

The product of its (nonzero) digits is 88179840, while the sum is 68.

The spelling of 8156906397491 in words is "eight trillion, one hundred fifty-six billion, nine hundred six million, three hundred ninety-seven thousand, four hundred ninety-one".