81355541 has 2 divisors, whose sum is σ = 81355542. Its totient is φ = 81355540.

The previous prime is 81355493. The next prime is 81355607. The reversal of 81355541 is 14555318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67996516 + 13359025 = 8246^2 + 3655^2 .

It is a cyclic number.

It is not a de Polignac number, because 81355541 - 2¹⁰ = 81354517 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81355498 and 81355507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81355741) 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 as a sum of consecutive naturals, namely, 40677770 + 40677771.

It is an arithmetic number, because the mean of its divisors is an integer number (40677771).

Almost surely, 2^81355541 is an apocalyptic number.

It is an amenable number.

81355541 is a deficient number, since it is larger than the sum of its proper divisors (1).

81355541 is an equidigital number, since it uses as much as digits as its factorization.

81355541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12000, while the sum is 32.

The square root of 81355541 is about 9019.7306500804. The cubic root of 81355541 is about 433.3070074079.

The spelling of 81355541 in words is "eighty-one million, three hundred fifty-five thousand, five hundred forty-one".