81638600 has 48 divisors (see below), whose sum is σ = 192249600. Its totient is φ = 32235840.

The previous prime is 81638597. The next prime is 81638621. The reversal of 81638600 is 683618.

It is a super-2 number, since 2×81638600² = 13329722019920000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13217 + ... + 18383.

It is an arithmetic number, because the mean of its divisors is an integer number (4005200).

Almost surely, 2^81638600 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 81638600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96124800).

81638600 is an abundant number, since it is smaller than the sum of its proper divisors (110611000).

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

81638600 is a wasteful number, since it uses less digits than its factorization.

81638600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5262 (or 5253 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 81638600 is about 9035.4081258126. The cubic root of 81638600 is about 433.8089583696.

The spelling of 81638600 in words is "eighty-one million, six hundred thirty-eight thousand, six hundred".