8157621866847 has 4 divisors (see below), whose sum is σ = 10876829155800. Its totient is φ = 5438414577896.

The previous prime is 8157621866819. The next prime is 8157621866857. The reversal of 8157621866847 is 7486681267518.

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 8157621866847 - 2¹⁸ = 8157621604703 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8157621866857) 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, 1359603644472 + ... + 1359603644477.

It is an arithmetic number, because the mean of its divisors is an integer number (2719207288950).

Almost surely, 2^{8157621866847} is an apocalyptic number.

8157621866847 is a deficient number, since it is larger than the sum of its proper divisors (2719207288953).

8157621866847 is a wasteful number, since it uses less digits than its factorization.

8157621866847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2719207288952.

The product of its digits is 216760320, while the sum is 69.

The spelling of 8157621866847 in words is "eight trillion, one hundred fifty-seven billion, six hundred twenty-one million, eight hundred sixty-six thousand, eight hundred forty-seven".