81401800 has 48 divisors (see below), whose sum is σ = 189959940. Its totient is φ = 32440320.

The previous prime is 81401783. The next prime is 81401809. The reversal of 81401800 is 810418.

It can be written as a sum of positive squares in 6 ways, for example, as 37920964 + 43480836 = 6158^2 + 6594^2 .

It is not an unprimeable number, because it can be changed into a prime (81401809) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 70024 + ... + 71176.

Almost surely, 2^81401800 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 81401800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94979970).

81401800 is an abundant number, since it is smaller than the sum of its proper divisors (108558140).

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

81401800 is a wasteful number, since it uses less digits than its factorization.

81401800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1522 (or 1513 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 81401800 is about 9022.2946083577. The cubic root of 81401800 is about 433.3891183935.

The spelling of 81401800 in words is "eighty-one million, four hundred one thousand, eight hundred".