81287506 has 8 divisors (see below), whose sum is σ = 129103740. Its totient is φ = 38252928.

The previous prime is 81287467. The next prime is 81287593. The reversal of 81287506 is 60578218.

It can be written as a sum of positive squares in 2 ways, for example, as 78481881 + 2805625 = 8859^2 + 1675^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1195371 + ... + 1195438.

Almost surely, 2^81287506 is an apocalyptic number.

81287506 is a deficient number, since it is larger than the sum of its proper divisors (47816234).

81287506 is a wasteful number, since it uses less digits than its factorization.

81287506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2390828.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 81287506 is about 9015.9584071800. The cubic root of 81287506 is about 433.1861868572.

The spelling of 81287506 in words is "eighty-one million, two hundred eighty-seven thousand, five hundred six".