81657167873 has 4 divisors (see below), whose sum is σ = 82067505600. Its totient is φ = 81246830148.

The previous prime is 81657167869. The next prime is 81657167887. The reversal of 81657167873 is 37876175618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81657167873 - 2² = 81657167869 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81657167843) 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, 205168565 + ... + 205168962.

It is an arithmetic number, because the mean of its divisors is an integer number (20516876400).

Almost surely, 2^81657167873 is an apocalyptic number.

It is an amenable number.

81657167873 is a deficient number, since it is larger than the sum of its proper divisors (410337727).

81657167873 is a wasteful number, since it uses less digits than its factorization.

81657167873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410337726.

The product of its digits is 11854080, while the sum is 59.

The spelling of 81657167873 in words is "eighty-one billion, six hundred fifty-seven million, one hundred sixty-seven thousand, eight hundred seventy-three".