81574646 has 4 divisors (see below), whose sum is σ = 122361972. Its totient is φ = 40787322.

The previous prime is 81574643. The next prime is 81574663. The reversal of 81574646 is 64647518.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81574643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20393660 + ... + 20393663.

It is an arithmetic number, because the mean of its divisors is an integer number (30590493).

Almost surely, 2^81574646 is an apocalyptic number.

81574646 is a deficient number, since it is larger than the sum of its proper divisors (40787326).

81574646 is a wasteful number, since it uses less digits than its factorization.

81574646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40787325.

The product of its digits is 161280, while the sum is 41.

The square root of 81574646 is about 9031.8683559937. The cubic root of 81574646 is about 433.6956497716.

The spelling of 81574646 in words is "eighty-one million, five hundred seventy-four thousand, six hundred forty-six".