81377265 has 16 divisors (see below), whose sum is σ = 130749696. Its totient is φ = 43219200.

The previous prime is 81377237. The next prime is 81377273. The reversal of 81377265 is 56277318.

It is not a de Polignac number, because 81377265 - 2¹⁹ = 80852977 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7641 + ... + 14870.

It is an arithmetic number, because the mean of its divisors is an integer number (8171856).

Almost surely, 2^81377265 is an apocalyptic number.

It is an amenable number.

81377265 is a deficient number, since it is larger than the sum of its proper divisors (49372431).

81377265 is a wasteful number, since it uses less digits than its factorization.

81377265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22760.

The product of its digits is 70560, while the sum is 39.

The square root of 81377265 is about 9020.9348185208. The cubic root of 81377265 is about 433.3455719752.

The spelling of 81377265 in words is "eighty-one million, three hundred seventy-seven thousand, two hundred sixty-five".