81494540 has 24 divisors (see below), whose sum is σ = 171345552. Its totient is φ = 32558400.

The previous prime is 81494537. The next prime is 81494561. The reversal of 81494540 is 4549418.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81494540.

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, 19082 + ... + 22958.

It is an arithmetic number, because the mean of its divisors is an integer number (7139398).

Almost surely, 2^81494540 is an apocalyptic number.

It is an amenable number.

81494540 is an abundant number, since it is smaller than the sum of its proper divisors (89851012).

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

81494540 is a wasteful number, since it uses less digits than its factorization.

81494540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4937 (or 4935 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 35.

The square root of 81494540 is about 9027.4326361375. The cubic root of 81494540 is about 433.5536407705.

The spelling of 81494540 in words is "eighty-one million, four hundred ninety-four thousand, five hundred forty".