81547388557 has 8 divisors (see below), whose sum is σ = 82367931776. Its totient is φ = 80727399792.

The previous prime is 81547388539. The next prime is 81547388567. The reversal of 81547388557 is 75588374518.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81547388557 - 2¹⁵ = 81547355789 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81547388495 and 81547388504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81547388567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160243 + ... + 434479.

It is an arithmetic number, because the mean of its divisors is an integer number (10295991472).

Almost surely, 2^81547388557 is an apocalyptic number.

It is an amenable number.

81547388557 is a deficient number, since it is larger than the sum of its proper divisors (820543219).

81547388557 is a wasteful number, since it uses less digits than its factorization.

81547388557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277227.

The product of its digits is 37632000, while the sum is 61.

The spelling of 81547388557 in words is "eighty-one billion, five hundred forty-seven million, three hundred eighty-eight thousand, five hundred fifty-seven".