81275405 has 4 divisors (see below), whose sum is σ = 97530492. Its totient is φ = 65020320.

The previous prime is 81275377. The next prime is 81275431. The reversal of 81275405 is 50457218.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31685641 + 49589764 = 5629^2 + 7042^2 .

It is not a de Polignac number, because 81275405 - 2¹⁴ = 81259021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8127536 + ... + 8127545.

It is an arithmetic number, because the mean of its divisors is an integer number (24382623).

Almost surely, 2^81275405 is an apocalyptic number.

It is an amenable number.

81275405 is a deficient number, since it is larger than the sum of its proper divisors (16255087).

81275405 is a wasteful number, since it uses less digits than its factorization.

81275405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16255086.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 81275405 is about 9015.2872943684. The cubic root of 81275405 is about 433.1646901293.

The spelling of 81275405 in words is "eighty-one million, two hundred seventy-five thousand, four hundred five".