81257889132 has 108 divisors (see below), whose sum is σ = 241051965336. Its totient is φ = 23011027200.

The previous prime is 81257889131. The next prime is 81257889187. The reversal of 81257889132 is 23198875218.

It is not an unprimeable number, because it can be changed into a prime (81257889131) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4494 + ... + 403157.

It is an arithmetic number, because the mean of its divisors is an integer number (2231962642).

Almost surely, 2^81257889132 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 81257889132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120525982668).

81257889132 is an abundant number, since it is smaller than the sum of its proper divisors (159794076204).

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

81257889132 is a wasteful number, since it uses less digits than its factorization.

81257889132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407788 (or 407776 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 54.

The spelling of 81257889132 in words is "eighty-one billion, two hundred fifty-seven million, eight hundred eighty-nine thousand, one hundred thirty-two".