81257240080 has 20 divisors (see below), whose sum is σ = 188923083372. Its totient is φ = 32502896000.

The previous prime is 81257239937. The next prime is 81257240081. The reversal of 81257240080 is 8004275218.

It can be written as a sum of positive squares in 2 ways, for example, as 52686775296 + 28570464784 = 229536^2 + 169028^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (81257240081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 507857671 + ... + 507857830.

Almost surely, 2^81257240080 is an apocalyptic number.

81257240080 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81257240080 is an abundant number, since it is smaller than the sum of its proper divisors (107665843292).

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

81257240080 is a wasteful number, since it uses less digits than its factorization.

81257240080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015715514 (or 1015715508 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 37.

The spelling of 81257240080 in words is "eighty-one billion, two hundred fifty-seven million, two hundred forty thousand, eighty".