81293900159 has 4 divisors (see below), whose sum is σ = 86075894304. Its totient is φ = 76511906016.

The previous prime is 81293900143. The next prime is 81293900189. The reversal of 81293900159 is 95100939218.

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 81293900159 - 2⁴ = 81293900143 is a prime.

It is a super-2 number, since 2×81293900159² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81293900119) 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, 2390997047 + ... + 2390997080.

It is an arithmetic number, because the mean of its divisors is an integer number (21518973576).

Almost surely, 2^81293900159 is an apocalyptic number.

81293900159 is a deficient number, since it is larger than the sum of its proper divisors (4781994145).

81293900159 is a wasteful number, since it uses less digits than its factorization.

81293900159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4781994144.

The product of its (nonzero) digits is 174960, while the sum is 47.

The spelling of 81293900159 in words is "eighty-one billion, two hundred ninety-three million, nine hundred thousand, one hundred fifty-nine".