81385493265 has 24 divisors (see below), whose sum is σ = 141577481448. Its totient is φ = 43248890880.

The previous prime is 81385493249. The next prime is 81385493347. The reversal of 81385493265 is 56239458318.

81385493265 is a `hidden beast` number, since 8 + 1 + 3 + 8 + 549 + 32 + 65 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 999634689 + 80385858576 = 31617^2 + 283524^2 .

It is not a de Polignac number, because 81385493265 - 2⁴ = 81385493249 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 23 ways as a sum of consecutive naturals, for example, 3252096 + ... + 3277025.

It is an arithmetic number, because the mean of its divisors is an integer number (5899061727).

Almost surely, 2^81385493265 is an apocalyptic number.

It is an amenable number.

81385493265 is a deficient number, since it is larger than the sum of its proper divisors (60191988183).

81385493265 is a wasteful number, since it uses less digits than its factorization.

81385493265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6529409 (or 6529406 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 54.

The spelling of 81385493265 in words is "eighty-one billion, three hundred eighty-five million, four hundred ninety-three thousand, two hundred sixty-five".