81329976 has 96 divisors (see below), whose sum is σ = 271121760. Its totient is φ = 21447936.

The previous prime is 81329971. The next prime is 81329977. The reversal of 81329976 is 67992318.

It is a super-2 number, since 2×81329976² = 13229129992321152, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81329971) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 346 + ... + 12758.

It is an arithmetic number, because the mean of its divisors is an integer number (2824185).

Almost surely, 2^81329976 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 81329976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135560880).

81329976 is an abundant number, since it is smaller than the sum of its proper divisors (189791784).

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

81329976 is a wasteful number, since it uses less digits than its factorization.

81329976 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12445 (or 12438 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 81329976 is about 9018.3133678089. The cubic root of 81329976 is about 433.2616154816.

The spelling of 81329976 in words is "eighty-one million, three hundred twenty-nine thousand, nine hundred seventy-six".