81537623087 has 4 divisors (see below), whose sum is σ = 81629965560. Its totient is φ = 81445280616.

The previous prime is 81537623059. The next prime is 81537623113. The reversal of 81537623087 is 78032673518.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81537623087 - 2⁶ = 81537623023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81537623287) 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, 46169912 + ... + 46171677.

It is an arithmetic number, because the mean of its divisors is an integer number (20407491390).

Almost surely, 2^81537623087 is an apocalyptic number.

81537623087 is a deficient number, since it is larger than the sum of its proper divisors (92342473).

81537623087 is an equidigital number, since it uses as much as digits as its factorization.

81537623087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92342472.

The product of its (nonzero) digits is 1693440, while the sum is 50.

The spelling of 81537623087 in words is "eighty-one billion, five hundred thirty-seven million, six hundred twenty-three thousand, eighty-seven".