81868141 has 4 divisors (see below), whose sum is σ = 86683932. Its totient is φ = 77052352.

The previous prime is 81868133. The next prime is 81868147. The reversal of 81868141 is 14186818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62252100 + 19616041 = 7890^2 + 4429^2 .

It is a cyclic number.

It is not a de Polignac number, because 81868141 - 2³ = 81868133 is a prime.

It is a super-3 number, since 3×81868141³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81868141.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81868147) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2407870 + ... + 2407903.

It is an arithmetic number, because the mean of its divisors is an integer number (21670983).

Almost surely, 2^81868141 is an apocalyptic number.

It is an amenable number.

81868141 is a deficient number, since it is larger than the sum of its proper divisors (4815791).

81868141 is a wasteful number, since it uses less digits than its factorization.

81868141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4815790.

The product of its digits is 12288, while the sum is 37.

The square root of 81868141 is about 9048.1015135773. The cubic root of 81868141 is about 434.2151541386.

The spelling of 81868141 in words is "eighty-one million, eight hundred sixty-eight thousand, one hundred forty-one".