81695904 has 48 divisors (see below), whose sum is σ = 217056672. Its totient is φ = 26901248.

The previous prime is 81695893. The next prime is 81695909. The reversal of 81695904 is 40959618.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81695909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2842 + ... + 13094.

It is an arithmetic number, because the mean of its divisors is an integer number (4522014).

Almost surely, 2^81695904 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 81695904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108528336).

81695904 is an abundant number, since it is smaller than the sum of its proper divisors (135360768).

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

81695904 is a wasteful number, since it uses less digits than its factorization.

81695904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10349 (or 10341 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 81695904 is about 9038.5786493231. The cubic root of 81695904 is about 433.9104347727.

The spelling of 81695904 in words is "eighty-one million, six hundred ninety-five thousand, nine hundred four".