81297397213 has 8 divisors (see below), whose sum is σ = 82079008128. Its totient is φ = 80516190624.

The previous prime is 81297397169. The next prime is 81297397241. The reversal of 81297397213 is 31279379218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81297397213 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 (81297197213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 311020 + ... + 509242.

It is an arithmetic number, because the mean of its divisors is an integer number (10259876016).

Almost surely, 2^81297397213 is an apocalyptic number.

It is an amenable number.

81297397213 is a deficient number, since it is larger than the sum of its proper divisors (781610915).

81297397213 is a wasteful number, since it uses less digits than its factorization.

81297397213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202163.

The product of its digits is 1143072, while the sum is 52.

The spelling of 81297397213 in words is "eighty-one billion, two hundred ninety-seven million, three hundred ninety-seven thousand, two hundred thirteen".