81287492 has 24 divisors (see below), whose sum is σ = 167123712. Its totient is φ = 34106400.

The previous prime is 81287467. The next prime is 81287593. The reversal of 81287492 is 29478218.

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 7 ways as a sum of consecutive naturals, for example, 70484 + ... + 71627.

It is an arithmetic number, because the mean of its divisors is an integer number (6963488).

Almost surely, 2^81287492 is an apocalyptic number.

It is an amenable number.

81287492 is an abundant number, since it is smaller than the sum of its proper divisors (85836220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81287492 is a wasteful number, since it uses less digits than its factorization.

81287492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142139 (or 142137 counting only the distinct ones).

The product of its digits is 64512, while the sum is 41.

The square root of 81287492 is about 9015.9576307789. The cubic root of 81287492 is about 433.1861619882.

The spelling of 81287492 in words is "eighty-one million, two hundred eighty-seven thousand, four hundred ninety-two".