81575634113 has 4 divisors (see below), whose sum is σ = 85869088560. Its totient is φ = 77282179668.

The previous prime is 81575634043. The next prime is 81575634157. The reversal of 81575634113 is 31143657518.

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 81575634113 - 2¹⁶ = 81575568577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81575634163) 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, 2146727195 + ... + 2146727232.

It is an arithmetic number, because the mean of its divisors is an integer number (21467272140).

Almost surely, 2^81575634113 is an apocalyptic number.

It is an amenable number.

81575634113 is a deficient number, since it is larger than the sum of its proper divisors (4293454447).

81575634113 is a wasteful number, since it uses less digits than its factorization.

81575634113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4293454446.

The product of its digits is 302400, while the sum is 44.

The spelling of 81575634113 in words is "eighty-one billion, five hundred seventy-five million, six hundred thirty-four thousand, one hundred thirteen".