81985850352 has 400 divisors, whose sum is σ = 281793124800. Its totient is φ = 22515978240.

The previous prime is 81985850339. The next prime is 81985850389. The reversal of 81985850352 is 25305858918.

It is a happy number.

81985850352 is a `hidden beast` number, since 8 + 1 + 9 + 8 + 585 + 0 + 3 + 52 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 73927174 + ... + 73928282.

It is an arithmetic number, because the mean of its divisors is an integer number (704482812).

Almost surely, 2^81985850352 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 81985850352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140896562400).

81985850352 is an abundant number, since it is smaller than the sum of its proper divisors (199807274448).

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

81985850352 is a wasteful number, since it uses less digits than its factorization.

81985850352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1446 (or 1431 counting only the distinct ones).

The product of its (nonzero) digits is 3456000, while the sum is 54.

The spelling of 81985850352 in words is "eighty-one billion, nine hundred eighty-five million, eight hundred fifty thousand, three hundred fifty-two".