81359442 has 24 divisors (see below), whose sum is σ = 182358540. Its totient is φ = 26184480.

The previous prime is 81359437. The next prime is 81359461. The reversal of 81359442 is 24495318.

It can be written as a sum of positive squares in 2 ways, for example, as 72233001 + 9126441 = 8499^2 + 3021^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81359397 and 81359406.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 77409 + ... + 78452.

Almost surely, 2^81359442 is an apocalyptic number.

81359442 is an abundant number, since it is smaller than the sum of its proper divisors (100999098).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81359442 is a wasteful number, since it uses less digits than its factorization.

81359442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155898 (or 155895 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81359442 is about 9019.9468956308. The cubic root of 81359442 is about 433.3139329908.

The spelling of 81359442 in words is "eighty-one million, three hundred fifty-nine thousand, four hundred forty-two".