81329100 has 36 divisors (see below), whose sum is σ = 235313064. Its totient is φ = 21687680.

The previous prime is 81329077. The next prime is 81329107. The reversal of 81329100 is 192318.

It is a super-2 number, since 2×81329100² = 13228845013620000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81329107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 135249 + ... + 135848.

It is an arithmetic number, because the mean of its divisors is an integer number (6536474).

Almost surely, 2^81329100 is an apocalyptic number.

It is an amenable number.

81329100 is an abundant number, since it is smaller than the sum of its proper divisors (153983964).

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

81329100 is a wasteful number, since it uses less digits than its factorization.

81329100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271114 (or 271107 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 81329100 is about 9018.2647998382. The cubic root of 81329100 is about 433.2600599316.

The spelling of 81329100 in words is "eighty-one million, three hundred twenty-nine thousand, one hundred".