81880240581 has 32 divisors (see below), whose sum is σ = 124000665600. Its totient is φ = 53385084720.

The previous prime is 81880240579. The next prime is 81880240591. The reversal of 81880240581 is 18504208818.

It is not a de Polignac number, because 81880240581 - 2¹ = 81880240579 is a prime.

It is a super-2 number, since 2×81880240581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81880240531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 88636 + ... + 414266.

It is an arithmetic number, because the mean of its divisors is an integer number (3875020800).

Almost surely, 2^81880240581 is an apocalyptic number.

It is an amenable number.

81880240581 is a deficient number, since it is larger than the sum of its proper divisors (42120425019).

81880240581 is a wasteful number, since it uses less digits than its factorization.

81880240581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325846 (or 325840 counting only the distinct ones).

The product of its (nonzero) digits is 163840, while the sum is 45.

The spelling of 81880240581 in words is "eighty-one billion, eight hundred eighty million, two hundred forty thousand, five hundred eighty-one".