81287495 has 4 divisors (see below), whose sum is σ = 97545000. Its totient is φ = 65029992.

The previous prime is 81287467. The next prime is 81287593. The reversal of 81287495 is 59478218.

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

It is a cyclic number.

It is not a de Polignac number, because 81287495 - 2⁶ = 81287431 is a prime.

It is a congruent 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 3 ways as a sum of consecutive naturals, for example, 8128745 + ... + 8128754.

It is an arithmetic number, because the mean of its divisors is an integer number (24386250).

Almost surely, 2^81287495 is an apocalyptic number.

81287495 is a deficient number, since it is larger than the sum of its proper divisors (16257505).

81287495 is a wasteful number, since it uses less digits than its factorization.

81287495 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16257504.

The product of its digits is 161280, while the sum is 44.

The square root of 81287495 is about 9015.9577971506. The cubic root of 81287495 is about 433.1861673173.

The spelling of 81287495 in words is "eighty-one million, two hundred eighty-seven thousand, four hundred ninety-five".