81995541 has 4 divisors (see below), whose sum is σ = 109327392. Its totient is φ = 54663692.

The previous prime is 81995533. The next prime is 81995569. The reversal of 81995541 is 14559918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81995541 - 2³ = 81995533 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81995493 and 81995502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81995581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13665921 + ... + 13665926.

It is an arithmetic number, because the mean of its divisors is an integer number (27331848).

Almost surely, 2^81995541 is an apocalyptic number.

It is an amenable number.

81995541 is a deficient number, since it is larger than the sum of its proper divisors (27331851).

81995541 is a wasteful number, since it uses less digits than its factorization.

81995541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27331850.

The product of its digits is 64800, while the sum is 42.

The square root of 81995541 is about 9055.1389277029. The cubic root of 81995541 is about 434.4402736199.

The spelling of 81995541 in words is "eighty-one million, nine hundred ninety-five thousand, five hundred forty-one".