81331402 has 16 divisors (see below), whose sum is σ = 126211680. Its totient is φ = 39277008.

The previous prime is 81331379. The next prime is 81331403. The reversal of 81331402 is 20413318.

It is a super-2 number, since 2×81331402² = 13229593902571208, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81331403) 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 7 ways as a sum of consecutive naturals, for example, 6333 + ... + 14239.

It is an arithmetic number, because the mean of its divisors is an integer number (7888230).

Almost surely, 2^81331402 is an apocalyptic number.

81331402 is a deficient number, since it is larger than the sum of its proper divisors (44880278).

81331402 is a wasteful number, since it uses less digits than its factorization.

81331402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8085.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 81331402 is about 9018.3924288090. The cubic root of 81331402 is about 433.2641476658.

The spelling of 81331402 in words is "eighty-one million, three hundred thirty-one thousand, four hundred two".