81601642080 has 480 divisors, whose sum is σ = 329981008896. Its totient is φ = 18603426816.

The previous prime is 81601642039. The next prime is 81601642091. The reversal of 81601642080 is 8024610618.

81601642080 is a `hidden beast` number, since 8 + 1 + 6 + 0 + 1 + 642 + 0 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 44179717 + ... + 44181563.

Almost surely, 2^81601642080 is an apocalyptic number.

81601642080 is a gapful number since it is divisible by the number (80) 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 81601642080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (164990504448).

81601642080 is an abundant number, since it is smaller than the sum of its proper divisors (248379366816).

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

81601642080 is a wasteful number, since it uses less digits than its factorization.

81601642080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2368 (or 2351 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The spelling of 81601642080 in words is "eighty-one billion, six hundred one million, six hundred forty-two thousand, eighty".