81318042 has 24 divisors (see below), whose sum is σ = 189742644. Its totient is φ = 25020864.

The previous prime is 81318023. The next prime is 81318067. The reversal of 81318042 is 24081318.

It can be written as a sum of positive squares in 2 ways, for example, as 75012921 + 6305121 = 8661^2 + 2511^2 .

It is a super-2 number, since 2×81318042² = 13225247909427528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81317997 and 81318015.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173523 + ... + 173990.

Almost surely, 2^81318042 is an apocalyptic number.

81318042 is an abundant number, since it is smaller than the sum of its proper divisors (108424602).

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

81318042 is a wasteful number, since it uses less digits than its factorization.

81318042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347534 (or 347531 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81318042 is about 9017.6516898802. The cubic root of 81318042 is about 433.2404228156.

The spelling of 81318042 in words is "eighty-one million, three hundred eighteen thousand, forty-two".