81575444240 has 40 divisors (see below), whose sum is σ = 192063719040. Its totient is φ = 32217134976.

The previous prime is 81575444201. The next prime is 81575444261. The reversal of 81575444240 is 4244457518.

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

It is a junction number, because it is equal to n+sod(n) for n = 81575444191 and 81575444200.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6447434 + ... + 6460073.

It is an arithmetic number, because the mean of its divisors is an integer number (4801592976).

Almost surely, 2^81575444240 is an apocalyptic number.

81575444240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81575444240 is an abundant number, since it is smaller than the sum of its proper divisors (110488274800).

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

81575444240 is a wasteful number, since it uses less digits than its factorization.

81575444240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12907599 (or 12907593 counting only the distinct ones).

The product of its (nonzero) digits is 716800, while the sum is 44.

The spelling of 81575444240 in words is "eighty-one billion, five hundred seventy-five million, four hundred forty-four thousand, two hundred forty".