81639096 has 96 divisors (see below), whose sum is σ = 259044480. Its totient is φ = 21201600.

The previous prime is 81639073. The next prime is 81639109. The reversal of 81639096 is 69093618.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9781 + ... + 16091.

It is an arithmetic number, because the mean of its divisors is an integer number (2698380).

Almost surely, 2^81639096 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 81639096, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129522240).

81639096 is an abundant number, since it is smaller than the sum of its proper divisors (177405384).

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

81639096 is a wasteful number, since it uses less digits than its factorization.

81639096 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6345 (or 6334 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 81639096 is about 9035.4355733412. The cubic root of 81639096 is about 433.8098369116.

The spelling of 81639096 in words is "eighty-one million, six hundred thirty-nine thousand, ninety-six".