81401856 has 48 divisors (see below), whose sum is σ = 217035000. Its totient is φ = 27131904.

The previous prime is 81401839. The next prime is 81401891. The reversal of 81401856 is 65810418.

It is a tau number, because it is divible by the number of its divisors (48).

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, 481 + ... + 12768.

Almost surely, 2^81401856 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 81401856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108517500).

81401856 is an abundant number, since it is smaller than the sum of its proper divisors (135633144).

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

81401856 is a wasteful number, since it uses less digits than its factorization.

81401856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13274 (or 13254 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 81401856 is about 9022.2977117805. The cubic root of 81401856 is about 433.3892177762.

The spelling of 81401856 in words is "eighty-one million, four hundred one thousand, eight hundred fifty-six".