81897088 has 128 divisors (see below), whose sum is σ = 205632000. Its totient is φ = 31629312.

The previous prime is 81897083. The next prime is 81897091. The reversal of 81897088 is 88079818.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (81897083) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 920148 + ... + 920236.

It is an arithmetic number, because the mean of its divisors is an integer number (1606500).

Almost surely, 2^81897088 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 81897088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102816000).

81897088 is an abundant number, since it is smaller than the sum of its proper divisors (123734912).

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

81897088 is a wasteful number, since it uses less digits than its factorization.

81897088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 49.

The square root of 81897088 is about 9049.7009895355. The cubic root of 81897088 is about 434.2663248170.

The spelling of 81897088 in words is "eighty-one million, eight hundred ninety-seven thousand, eighty-eight".