81895860 has 168 divisors, whose sum is σ = 266071176. Its totient is φ = 21150720.

The previous prime is 81895843. The next prime is 81895921. The reversal of 81895860 is 6859818.

It can be written as a sum of positive squares in 4 ways, for example, as 571536 + 81324324 = 756^2 + 9018^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 597712 + ... + 597848.

It is an arithmetic number, because the mean of its divisors is an integer number (1583757).

Almost surely, 2^81895860 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 81895860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133035588).

81895860 is an abundant number, since it is smaller than the sum of its proper divisors (184175316).

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

81895860 is a wasteful number, since it uses less digits than its factorization.

81895860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The square root of 81895860 is about 9049.6331417356. The cubic root of 81895860 is about 434.2641542810.

The spelling of 81895860 in words is "eighty-one million, eight hundred ninety-five thousand, eight hundred sixty".