81660141 has 12 divisors (see below), whose sum is σ = 118607580. Its totient is φ = 54138240.

The previous prime is 81660133. The next prime is 81660149. The reversal of 81660141 is 14106618.

81660141 is a `hidden beast` number, since 8 + 16 + 601 + 41 = 666.

It is an interprime number because it is at equal distance from previous prime (81660133) and next prime (81660149).

It can be written as a sum of positive squares in 2 ways, for example, as 37822500 + 43837641 = 6150^2 + 6621^2 .

It is not a de Polignac number, because 81660141 - 2³ = 81660133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81660149) 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, 23436 + ... + 26693.

It is an arithmetic number, because the mean of its divisors is an integer number (9883965).

Almost surely, 2^81660141 is an apocalyptic number.

It is an amenable number.

81660141 is a deficient number, since it is larger than the sum of its proper divisors (36947439).

81660141 is a wasteful number, since it uses less digits than its factorization.

81660141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50316 (or 50313 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81660141 is about 9036.6000796760. The cubic root of 81660141 is about 433.8471096731.

Adding to 81660141 its reverse (14106618), we get a palindrome (95766759).

The spelling of 81660141 in words is "eighty-one million, six hundred sixty thousand, one hundred forty-one".