81406944 has 216 divisors, whose sum is σ = 262112760. Its totient is φ = 24820992.

The previous prime is 81406939. The next prime is 81406957. The reversal of 81406944 is 44960418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (216).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81406899 and 81406908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2807122 + ... + 2807150.

It is an arithmetic number, because the mean of its divisors is an integer number (1213485).

Almost surely, 2^81406944 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81406944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131056380).

81406944 is an abundant number, since it is smaller than the sum of its proper divisors (180705816).

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

81406944 is a wasteful number, since it uses less digits than its factorization.

81406944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 81406944 is about 9022.5796754587. The cubic root of 81406944 is about 433.3982472116.

The spelling of 81406944 in words is "eighty-one million, four hundred six thousand, nine hundred forty-four".