81278541 has 6 divisors (see below), whose sum is σ = 117402350. Its totient is φ = 54185688.

The previous prime is 81278537. The next prime is 81278551. The reversal of 81278541 is 14587218.

It can be written as a sum of positive squares in only one way, i.e., 80622441 + 656100 = 8979^2 + 810^2 .

It is not a de Polignac number, because 81278541 - 2² = 81278537 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81278496 and 81278505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81278501) 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 5 ways as a sum of consecutive naturals, for example, 4515466 + ... + 4515483.

Almost surely, 2^81278541 is an apocalyptic number.

It is an amenable number.

81278541 is a deficient number, since it is larger than the sum of its proper divisors (36123809).

81278541 is a wasteful number, since it uses less digits than its factorization.

81278541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9030955 (or 9030952 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 81278541 is about 9015.4612194829. The cubic root of 81278541 is about 433.1702612571.

The spelling of 81278541 in words is "eighty-one million, two hundred seventy-eight thousand, five hundred forty-one".