81844340 has 48 divisors (see below), whose sum is σ = 179311104. Its totient is φ = 31344000.

The previous prime is 81844337. The next prime is 81844369. The reversal of 81844340 is 4344818.

It is a junction number, because it is equal to n+sod(n) for n = 81844297 and 81844306.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61967 + ... + 63273.

It is an arithmetic number, because the mean of its divisors is an integer number (3735648).

Almost surely, 2^81844340 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 81844340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89655552).

81844340 is an abundant number, since it is smaller than the sum of its proper divisors (97466764).

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

81844340 is a wasteful number, since it uses less digits than its factorization.

81844340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1448 (or 1446 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 32.

The square root of 81844340 is about 9046.7861696848. The cubic root of 81844340 is about 434.1730711971.

The spelling of 81844340 in words is "eighty-one million, eight hundred forty-four thousand, three hundred forty".