81437331 has 4 divisors (see below), whose sum is σ = 108583112. Its totient is φ = 54291552.

The previous prime is 81437311. The next prime is 81437339. The reversal of 81437331 is 13373418.

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

It is not a de Polignac number, because 81437331 - 2⁹ = 81436819 is a prime.

It is a super-2 number, since 2×81437331² = 13264077760807122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81437339) 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 3 ways as a sum of consecutive naturals, for example, 13572886 + ... + 13572891.

It is an arithmetic number, because the mean of its divisors is an integer number (27145778).

Almost surely, 2^81437331 is an apocalyptic number.

81437331 is a deficient number, since it is larger than the sum of its proper divisors (27145781).

81437331 is a wasteful number, since it uses less digits than its factorization.

81437331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27145780.

The product of its digits is 6048, while the sum is 30.

The square root of 81437331 is about 9024.2634602498. The cubic root of 81437331 is about 433.4521657661.

The spelling of 81437331 in words is "eighty-one million, four hundred thirty-seven thousand, three hundred thirty-one".