81041780 has 12 divisors (see below), whose sum is σ = 170187780. Its totient is φ = 32416704.

The previous prime is 81041777. The next prime is 81041797. The reversal of 81041780 is 8714018.

It can be written as a sum of positive squares in 2 ways, for example, as 29833444 + 51208336 = 5462^2 + 7156^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2026025 + ... + 2026064.

It is an arithmetic number, because the mean of its divisors is an integer number (14182315).

Almost surely, 2^81041780 is an apocalyptic number.

It is an amenable number.

81041780 is an abundant number, since it is smaller than the sum of its proper divisors (89146000).

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

81041780 is a wasteful number, since it uses less digits than its factorization.

81041780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4052098 (or 4052096 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 81041780 is about 9002.3208118796. The cubic root of 81041780 is about 432.7492498944.

Adding to 81041780 its reverse (8714018), we get a palindrome (89755798).

The spelling of 81041780 in words is "eighty-one million, forty-one thousand, seven hundred eighty".