81937018352 has 120 divisors (see below), whose sum is σ = 191263472640. Its totient is φ = 33883570560.

The previous prime is 81937018351. The next prime is 81937018367. The reversal of 81937018352 is 25381073918.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a junction number, because it is equal to n+sod(n) for n = 81937018297 and 81937018306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81937018351) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2600549 + ... + 2631867.

It is an arithmetic number, because the mean of its divisors is an integer number (1593862272).

Almost surely, 2^81937018352 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 81937018352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95631736320).

81937018352 is an abundant number, since it is smaller than the sum of its proper divisors (109326454288).

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

81937018352 is a wasteful number, since it uses less digits than its factorization.

81937018352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31459 (or 31446 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 47.

The spelling of 81937018352 in words is "eighty-one billion, nine hundred thirty-seven million, eighteen thousand, three hundred fifty-two".