81481433816 has 16 divisors (see below), whose sum is σ = 156028278240. Its totient is φ = 39873892960.

The previous prime is 81481433773. The next prime is 81481433821. The reversal of 81481433816 is 61833418418.

It is a super-2 number, since 2×81481433816² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108352595 + ... + 108353346.

It is an arithmetic number, because the mean of its divisors is an integer number (9751767390).

Almost surely, 2^81481433816 is an apocalyptic number.

It is an amenable number.

81481433816 is a deficient number, since it is larger than the sum of its proper divisors (74546844424).

81481433816 is a wasteful number, since it uses less digits than its factorization.

81481433816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216705994 (or 216705990 counting only the distinct ones).

The product of its digits is 442368, while the sum is 47.

The spelling of 81481433816 in words is "eighty-one billion, four hundred eighty-one million, four hundred thirty-three thousand, eight hundred sixteen".