81571113053 has 4 divisors (see below), whose sum is σ = 81604864380. Its totient is φ = 81537361728.

The previous prime is 81571113023. The next prime is 81571113061. The reversal of 81571113053 is 35031117518.

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

It can be written as a sum of positive squares in 2 ways, for example, as 51257865604 + 30313247449 = 226402^2 + 174107^2 .

It is a cyclic number.

It is not a de Polignac number, because 81571113053 - 2²⁸ = 81302677597 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 (81571113023) 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, 16872038 + ... + 16876871.

It is an arithmetic number, because the mean of its divisors is an integer number (20401216095).

Almost surely, 2^81571113053 is an apocalyptic number.

It is an amenable number.

81571113053 is a deficient number, since it is larger than the sum of its proper divisors (33751327).

81571113053 is a wasteful number, since it uses less digits than its factorization.

81571113053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33751326.

The product of its (nonzero) digits is 12600, while the sum is 35.

The spelling of 81571113053 in words is "eighty-one billion, five hundred seventy-one million, one hundred thirteen thousand, fifty-three".