81436541 has 2 divisors, whose sum is σ = 81436542. Its totient is φ = 81436540.

The previous prime is 81436507. The next prime is 81436547. The reversal of 81436541 is 14563418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73170916 + 8265625 = 8554^2 + 2875^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81436541 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81436498 and 81436507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81436547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40718270 + 40718271.

It is an arithmetic number, because the mean of its divisors is an integer number (40718271).

Almost surely, 2^81436541 is an apocalyptic number.

It is an amenable number.

81436541 is a deficient number, since it is larger than the sum of its proper divisors (1).

81436541 is an equidigital number, since it uses as much as digits as its factorization.

81436541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 32.

The square root of 81436541 is about 9024.2196892585. The cubic root of 81436541 is about 433.4507641635.

Adding to 81436541 its reverse (14563418), we get a palindrome (95999959).

The spelling of 81436541 in words is "eighty-one million, four hundred thirty-six thousand, five hundred forty-one".