81385140534 has 16 divisors (see below), whose sum is σ = 168020935680. Its totient is φ = 26253271080.

The previous prime is 81385140527. The next prime is 81385140539. The reversal of 81385140534 is 43504158318.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81385140539) 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, 218777074 + ... + 218777445.

It is an arithmetic number, because the mean of its divisors is an integer number (10501308480).

Almost surely, 2^81385140534 is an apocalyptic number.

81385140534 is an abundant number, since it is smaller than the sum of its proper divisors (86635795146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81385140534 is a wasteful number, since it uses less digits than its factorization.

81385140534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437554555.

The product of its (nonzero) digits is 230400, while the sum is 42.

The spelling of 81385140534 in words is "eighty-one billion, three hundred eighty-five million, one hundred forty thousand, five hundred thirty-four".