81512712 has 48 divisors (see below), whose sum is σ = 221530140. Its totient is φ = 27076608.

The previous prime is 81512699. The next prime is 81512719. The reversal of 81512712 is 21721518.

81512712 is a `hidden beast` number, since 81 + 512 + 71 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 46867716 + 34644996 = 6846^2 + 5886^2 .

It is not an unprimeable number, because it can be changed into a prime (81512719) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20728 + ... + 24344.

Almost surely, 2^81512712 is an apocalyptic number.

It is an amenable number.

81512712 is an abundant number, since it is smaller than the sum of its proper divisors (140017428).

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

81512712 is a wasteful number, since it uses less digits than its factorization.

81512712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3942 (or 3935 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 81512712 is about 9028.4390677459. The cubic root of 81512712 is about 433.5858635887.

The spelling of 81512712 in words is "eighty-one million, five hundred twelve thousand, seven hundred twelve".