81537792 has 144 divisors (see below), whose sum is σ = 257053440. Its totient is φ = 22450176.

The previous prime is 81537791. The next prime is 81537851. The reversal of 81537792 is 29773518.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81537791) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155643 + ... + 156165.

Almost surely, 2^81537792 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 81537792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128526720).

81537792 is an abundant number, since it is smaller than the sum of its proper divisors (175515648).

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

81537792 is a wasteful number, since it uses less digits than its factorization.

81537792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 578 (or 564 counting only the distinct ones).

The product of its digits is 105840, while the sum is 42.

The square root of 81537792 is about 9029.8279053368. The cubic root of 81537792 is about 433.6303278942.

The spelling of 81537792 in words is "eighty-one million, five hundred thirty-seven thousand, seven hundred ninety-two".