81357296 has 40 divisors (see below), whose sum is σ = 165562320. Its totient is φ = 38674944.

The previous prime is 81357271. The next prime is 81357307. The reversal of 81357296 is 69275318.

It is a super-2 number, since 2×81357296² = 13238019224863232, which contains 22 as substring.

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, 29780 + ... + 32396.

It is an arithmetic number, because the mean of its divisors is an integer number (4139058).

Almost surely, 2^81357296 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 81357296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82781160).

81357296 is an abundant number, since it is smaller than the sum of its proper divisors (84205024).

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

81357296 is a wasteful number, since it uses less digits than its factorization.

81357296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721 (or 2715 counting only the distinct ones).

The product of its digits is 90720, while the sum is 41.

The square root of 81357296 is about 9019.8279362746. The cubic root of 81357296 is about 433.3101231487.

The spelling of 81357296 in words is "eighty-one million, three hundred fifty-seven thousand, two hundred ninety-six".