81957336 has 64 divisors (see below), whose sum is σ = 217036800. Its totient is φ = 25718400.

The previous prime is 81957329. The next prime is 81957347. The reversal of 81957336 is 63375918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86626 + ... + 87566.

It is an arithmetic number, because the mean of its divisors is an integer number (3391200).

Almost surely, 2^81957336 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 81957336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108518400).

81957336 is an abundant number, since it is smaller than the sum of its proper divisors (135079464).

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

81957336 is a wasteful number, since it uses less digits than its factorization.

81957336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160 (or 1156 counting only the distinct ones).

The product of its digits is 136080, while the sum is 42.

The square root of 81957336 is about 9053.0291063268. The cubic root of 81957336 is about 434.3727887747.

The spelling of 81957336 in words is "eighty-one million, nine hundred fifty-seven thousand, three hundred thirty-six".