81318742 has 16 divisors (see below), whose sum is σ = 125012160. Its totient is φ = 39654208.

The previous prime is 81318709. The next prime is 81318779. The reversal of 81318742 is 24781318.

It is a happy number.

It is a super-2 number, since 2×81318742² = 13225475600925128, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81318698 and 81318707.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28434 + ... + 31162.

It is an arithmetic number, because the mean of its divisors is an integer number (7813260).

Almost surely, 2^81318742 is an apocalyptic number.

81318742 is a deficient number, since it is larger than the sum of its proper divisors (43693418).

81318742 is a wasteful number, since it uses less digits than its factorization.

81318742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3095.

The product of its digits is 10752, while the sum is 34.

The square root of 81318742 is about 9017.6905025622. The cubic root of 81318742 is about 433.2416659486.

The spelling of 81318742 in words is "eighty-one million, three hundred eighteen thousand, seven hundred forty-two".