81525771 has 24 divisors (see below), whose sum is σ = 123243120. Its totient is φ = 53851392.

The previous prime is 81525767. The next prime is 81525779. The reversal of 81525771 is 17752518.

81525771 is a `hidden beast` number, since 81 + 5 + 2 + 577 + 1 = 666.

It is not a de Polignac number, because 81525771 - 2² = 81525767 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81525779) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25975 + ... + 28943.

It is an arithmetic number, because the mean of its divisors is an integer number (5135130).

Almost surely, 2^81525771 is an apocalyptic number.

81525771 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81525771 is a deficient number, since it is larger than the sum of its proper divisors (41717349).

81525771 is a wasteful number, since it uses less digits than its factorization.

81525771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3097 (or 3085 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The square root of 81525771 is about 9029.1622534984. The cubic root of 81525771 is about 433.6090170139.

The spelling of 81525771 in words is "eighty-one million, five hundred twenty-five thousand, seven hundred seventy-one".