81000026213 has 4 divisors (see below), whose sum is σ = 81543650700. Its totient is φ = 80456401728.

The previous prime is 81000026203. The next prime is 81000026251. The reversal of 81000026213 is 31262000018.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10604262529 + 70395763684 = 102977^2 + 265322^2 .

It is a cyclic number.

It is not a de Polignac number, because 81000026213 - 2¹⁴ = 81000009829 is a prime.

It is a super-2 number, since 2×81000026213² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000026203) 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, 271812020 + ... + 271812317.

It is an arithmetic number, because the mean of its divisors is an integer number (20385912675).

Almost surely, 2^81000026213 is an apocalyptic number.

It is an amenable number.

81000026213 is a deficient number, since it is larger than the sum of its proper divisors (543624487).

81000026213 is a wasteful number, since it uses less digits than its factorization.

81000026213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543624486.

The product of its (nonzero) digits is 576, while the sum is 23.

The spelling of 81000026213 in words is "eighty-one billion, twenty-six thousand, two hundred thirteen".