81403944 has 16 divisors (see below), whose sum is σ = 203509920. Its totient is φ = 27134640.

The previous prime is 81403943. The next prime is 81403963. The reversal of 81403944 is 44930418.

It is a happy number.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81403943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1695892 + ... + 1695939.

It is an arithmetic number, because the mean of its divisors is an integer number (12719370).

Almost surely, 2^81403944 is an apocalyptic number.

It is an amenable number.

81403944 is an abundant number, since it is smaller than the sum of its proper divisors (122105976).

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

81403944 is a wasteful number, since it uses less digits than its factorization.

81403944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3391840 (or 3391836 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 81403944 is about 9022.4134243560. The cubic root of 81403944 is about 433.3929232975.

The spelling of 81403944 in words is "eighty-one million, four hundred three thousand, nine hundred forty-four".