81837256240 has 40 divisors (see below), whose sum is σ = 194912399808. Its totient is φ = 31936488960.

The previous prime is 81837256223. The next prime is 81837256243. The reversal of 81837256240 is 4265273818.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81837256243) 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 7 ways as a sum of consecutive naturals, for example, 12471912 + ... + 12478471.

Almost surely, 2^81837256240 is an apocalyptic number.

81837256240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81837256240 is an abundant number, since it is smaller than the sum of its proper divisors (113075143568).

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

81837256240 is a wasteful number, since it uses less digits than its factorization.

81837256240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24950437 (or 24950431 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 46.

The spelling of 81837256240 in words is "eighty-one billion, eight hundred thirty-seven million, two hundred fifty-six thousand, two hundred forty".