81605160 has 384 divisors, whose sum is σ = 339655680. Its totient is φ = 16533504.

The previous prime is 81605141. The next prime is 81605179. The reversal of 81605160 is 6150618.

It is an interprime number because it is at equal distance from previous prime (81605141) and next prime (81605179).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1539694 + ... + 1539746.

It is an arithmetic number, because the mean of its divisors is an integer number (884520).

Almost surely, 2^81605160 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 81605160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (169827840).

81605160 is an abundant number, since it is smaller than the sum of its proper divisors (258050520).

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

81605160 is a wasteful number, since it uses less digits than its factorization.

81605160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 81605160 is about 9033.5574387945. The cubic root of 81605160 is about 433.7497194283.

Adding to 81605160 its reverse (6150618), we get a palindrome (87755778).

The spelling of 81605160 in words is "eighty-one million, six hundred five thousand, one hundred sixty".