81549370 has 16 divisors (see below), whose sum is σ = 167758848. Its totient is φ = 27959760.

The previous prime is 81549361. The next prime is 81549373. The reversal of 81549370 is 7394518.

It is not an unprimeable number, because it can be changed into a prime (81549373) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 582426 + ... + 582565.

It is an arithmetic number, because the mean of its divisors is an integer number (10484928).

Almost surely, 2^81549370 is an apocalyptic number.

81549370 is an abundant number, since it is smaller than the sum of its proper divisors (86209478).

81549370 is a wasteful number, since it uses less digits than its factorization.

81549370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1165005.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81549370 is about 9030.4689800696. The cubic root of 81549370 is about 433.6508514420.

The spelling of 81549370 in words is "eighty-one million, five hundred forty-nine thousand, three hundred seventy".