81642534200 has 384 divisors, whose sum is σ = 212557824000. Its totient is φ = 29059430400.

The previous prime is 81642534173. The next prime is 81642534203. The reversal of 81642534200 is 243524618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81642534203) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 642854537 + ... + 642854663.

It is an arithmetic number, because the mean of its divisors is an integer number (553536000).

Almost surely, 2^81642534200 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 81642534200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106278912000).

81642534200 is an abundant number, since it is smaller than the sum of its proper divisors (130915289800).

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

81642534200 is a wasteful number, since it uses less digits than its factorization.

81642534200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 35.

The spelling of 81642534200 in words is "eighty-one billion, six hundred forty-two million, five hundred thirty-four thousand, two hundred".