81585125140 has 24 divisors (see below), whose sum is σ = 171336505032. Its totient is φ = 32632575360.

The previous prime is 81585125131. The next prime is 81585125143. The reversal of 81585125140 is 4152158518.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 831399556 + 80753725584 = 28834^2 + 284172^2 .

It is a super-2 number, since 2×81585125140² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81585125093 and 81585125102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81585125143) 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, 435030 + ... + 593650.

It is an arithmetic number, because the mean of its divisors is an integer number (7139021043).

Almost surely, 2^81585125140 is an apocalyptic number.

It is an amenable number.

81585125140 is an abundant number, since it is smaller than the sum of its proper divisors (89751379892).

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

81585125140 is a wasteful number, since it uses less digits than its factorization.

81585125140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184347 (or 184345 counting only the distinct ones).

The product of its (nonzero) digits is 64000, while the sum is 40.

The spelling of 81585125140 in words is "eighty-one billion, five hundred eighty-five million, one hundred twenty-five thousand, one hundred forty".