81540610 has 8 divisors (see below), whose sum is σ = 146773116. Its totient is φ = 32616240.

The previous prime is 81540601. The next prime is 81540617. The reversal of 81540610 is 1604518.

It can be written as a sum of positive squares in 2 ways, for example, as 78694641 + 2845969 = 8871^2 + 1687^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81540617) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 4077021 + ... + 4077040.

Almost surely, 2^81540610 is an apocalyptic number.

81540610 is a deficient number, since it is larger than the sum of its proper divisors (65232506).

81540610 is a wasteful number, since it uses less digits than its factorization.

81540610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8154068.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 81540610 is about 9029.9839423999. The cubic root of 81540610 is about 433.6353233536.

The spelling of 81540610 in words is "eighty-one million, five hundred forty thousand, six hundred ten".