81501536 has 48 divisors (see below), whose sum is σ = 170889264. Its totient is φ = 38129664.

The previous prime is 81501529. The next prime is 81501559. The reversal of 81501536 is 63510518.

It is a junction number, because it is equal to n+sod(n) for n = 81501499 and 81501508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126431 + ... + 127073.

It is an arithmetic number, because the mean of its divisors is an integer number (3560193).

Almost surely, 2^81501536 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 81501536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85444632).

81501536 is an abundant number, since it is smaller than the sum of its proper divisors (89387728).

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

81501536 is a wasteful number, since it uses less digits than its factorization.

81501536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903 (or 895 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 81501536 is about 9027.8201134050. The cubic root of 81501536 is about 433.5660467325.

The spelling of 81501536 in words is "eighty-one million, five hundred one thousand, five hundred thirty-six".