81557168 has 100 divisors (see below), whose sum is σ = 202142568. Its totient is φ = 31610880.

The previous prime is 81557129. The next prime is 81557207. The reversal of 81557168 is 86175518.

It is an interprime number because it is at equal distance from previous prime (81557129) and next prime (81557207).

Its product of digits (67200) is a multiple of the sum of its prime factors (240).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 422480 + ... + 422672.

Almost surely, 2^81557168 is an apocalyptic number.

81557168 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81557168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101071284).

81557168 is an abundant number, since it is smaller than the sum of its proper divisors (120585400).

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

81557168 is a wasteful number, since it uses less digits than its factorization.

81557168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240 (or 213 counting only the distinct ones).

The product of its digits is 67200, while the sum is 41.

The square root of 81557168 is about 9030.9007302705. The cubic root of 81557168 is about 433.6646733414.

The spelling of 81557168 in words is "eighty-one million, five hundred fifty-seven thousand, one hundred sixty-eight".