81279545 has 16 divisors (see below), whose sum is σ = 99221760. Its totient is φ = 63907584.

The previous prime is 81279529. The next prime is 81279553. The reversal of 81279545 is 54597218.

It is a cyclic number.

It is not a de Polignac number, because 81279545 - 2⁴ = 81279529 is a prime.

It is a Curzon number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 136769 + ... + 137361.

It is an arithmetic number, because the mean of its divisors is an integer number (6201360).

Almost surely, 2^81279545 is an apocalyptic number.

It is an amenable number.

81279545 is a deficient number, since it is larger than the sum of its proper divisors (17942215).

81279545 is a wasteful number, since it uses less digits than its factorization.

81279545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024.

The product of its digits is 100800, while the sum is 41.

The square root of 81279545 is about 9015.5169014317. The cubic root of 81279545 is about 433.1720448404.

The spelling of 81279545 in words is "eighty-one million, two hundred seventy-nine thousand, five hundred forty-five".