81588500437 has 4 divisors (see below), whose sum is σ = 81639272736. Its totient is φ = 81537728140.

The previous prime is 81588500393. The next prime is 81588500449. The reversal of 81588500437 is 73400588518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81588500437 - 2¹⁵ = 81588467669 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81588506437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25383739 + ... + 25386952.

It is an arithmetic number, because the mean of its divisors is an integer number (20409818184).

Almost surely, 2^81588500437 is an apocalyptic number.

It is an amenable number.

81588500437 is a deficient number, since it is larger than the sum of its proper divisors (50772299).

81588500437 is a wasteful number, since it uses less digits than its factorization.

81588500437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50772298.

The product of its (nonzero) digits is 1075200, while the sum is 49.

The spelling of 81588500437 in words is "eighty-one billion, five hundred eighty-eight million, five hundred thousand, four hundred thirty-seven".