81393844 has 24 divisors (see below), whose sum is σ = 163089920. Its totient is φ = 34818336.

The previous prime is 81393833. The next prime is 81393869. The reversal of 81393844 is 44839318.

It is a junction number, because it is equal to n+sod(n) for n = 81393797 and 81393806.

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, 14602 + ... + 19390.

Almost surely, 2^81393844 is an apocalyptic number.

It is an amenable number.

81393844 is an abundant number, since it is smaller than the sum of its proper divisors (81696076).

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

81393844 is a wasteful number, since it uses less digits than its factorization.

81393844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5407 (or 5405 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 81393844 is about 9021.8536897913. The cubic root of 81393844 is about 433.3749984921.

The spelling of 81393844 in words is "eighty-one million, three hundred ninety-three thousand, eight hundred forty-four".