81002905213 has 2 divisors, whose sum is σ = 81002905214. Its totient is φ = 81002905212.

The previous prime is 81002905169. The next prime is 81002905237. The reversal of 81002905213 is 31250920018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76373191449 + 4629713764 = 276357^2 + 68042^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81002905213 is a prime.

It is a super-2 number, since 2×81002905213² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81002905253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40501452606 + 40501452607.

It is an arithmetic number, because the mean of its divisors is an integer number (40501452607).

Almost surely, 2^81002905213 is an apocalyptic number.

It is an amenable number.

81002905213 is a deficient number, since it is larger than the sum of its proper divisors (1).

81002905213 is an equidigital number, since it uses as much as digits as its factorization.

81002905213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 81002905213 in words is "eighty-one billion, two million, nine hundred five thousand, two hundred thirteen".