81847229557 has 4 divisors (see below), whose sum is σ = 82337332896. Its totient is φ = 81357126220.

The previous prime is 81847229533. The next prime is 81847229579. The reversal of 81847229557 is 75592274818.

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 81847229557 - 2²⁷ = 81713011829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81847229507) 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, 245051419 + ... + 245051752.

It is an arithmetic number, because the mean of its divisors is an integer number (20584333224).

Almost surely, 2^81847229557 is an apocalyptic number.

It is an amenable number.

81847229557 is a deficient number, since it is larger than the sum of its proper divisors (490103339).

81847229557 is a wasteful number, since it uses less digits than its factorization.

81847229557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490103338.

The product of its digits is 11289600, while the sum is 58.

The spelling of 81847229557 in words is "eighty-one billion, eight hundred forty-seven million, two hundred twenty-nine thousand, five hundred fifty-seven".