81521174 has 16 divisors (see below), whose sum is σ = 140119200. Its totient is φ = 34845504.

The previous prime is 81521159. The next prime is 81521179. The reversal of 81521174 is 47112518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81521179) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2039 + ... + 12930.

It is an arithmetic number, because the mean of its divisors is an integer number (8757450).

Almost surely, 2^81521174 is an apocalyptic number.

81521174 is a deficient number, since it is larger than the sum of its proper divisors (58598026).

81521174 is a wasteful number, since it uses less digits than its factorization.

81521174 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15367.

The product of its digits is 2240, while the sum is 29.

The square root of 81521174 is about 9028.9076858721. The cubic root of 81521174 is about 433.6008668789.

The spelling of 81521174 in words is "eighty-one million, five hundred twenty-one thousand, one hundred seventy-four".