81226639 has 12 divisors (see below), whose sum is σ = 91784016. Its totient is φ = 71715072.

The previous prime is 81226637. The next prime is 81226667. The reversal of 81226639 is 93662218.

It is not a de Polignac number, because 81226639 - 2¹ = 81226637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81226598 and 81226607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81226631) 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 in 11 ways as a sum of consecutive naturals, for example, 6562 + ... + 14335.

It is an arithmetic number, because the mean of its divisors is an integer number (7648668).

Almost surely, 2^81226639 is an apocalyptic number.

81226639 is a deficient number, since it is larger than the sum of its proper divisors (10557377).

81226639 is a wasteful number, since it uses less digits than its factorization.

81226639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20946 (or 20933 counting only the distinct ones).

The product of its digits is 31104, while the sum is 37.

The square root of 81226639 is about 9012.5822603735. The cubic root of 81226639 is about 433.0780385136.

The spelling of 81226639 in words is "eighty-one million, two hundred twenty-six thousand, six hundred thirty-nine".