81760020 has 96 divisors (see below), whose sum is σ = 239016960. Its totient is φ = 20858880.

The previous prime is 81760013. The next prime is 81760037. The reversal of 81760020 is 2006718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 209986 + ... + 210374.

It is an arithmetic number, because the mean of its divisors is an integer number (2489760).

Almost surely, 2^81760020 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 81760020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119508480).

81760020 is an abundant number, since it is smaller than the sum of its proper divisors (157256940).

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

81760020 is a wasteful number, since it uses less digits than its factorization.

81760020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545 (or 543 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 81760020 is about 9042.1247503007. The cubic root of 81760020 is about 434.0239179270.

Adding to 81760020 its reverse (2006718), we get a palindrome (83766738).

The spelling of 81760020 in words is "eighty-one million, seven hundred sixty thousand, twenty".