81252106813 has 2 divisors, whose sum is σ = 81252106814. Its totient is φ = 81252106812.

The previous prime is 81252106783. The next prime is 81252106843. The reversal of 81252106813 is 31860125218.

It is a balanced prime because it is at equal distance from previous prime (81252106783) and next prime (81252106843).

It can be written as a sum of positive squares in only one way, i.e., 77923047609 + 3329059204 = 279147^2 + 57698^2 .

It is a cyclic number.

It is not a de Polignac number, because 81252106813 - 2³³ = 72662172221 is a prime.

It is a super-2 number, since 2×81252106813² (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 (81252106843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40626053406 + 40626053407.

It is an arithmetic number, because the mean of its divisors is an integer number (40626053407).

Almost surely, 2^81252106813 is an apocalyptic number.

It is an amenable number.

81252106813 is a deficient number, since it is larger than the sum of its proper divisors (1).

81252106813 is an equidigital number, since it uses as much as digits as its factorization.

81252106813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23040, while the sum is 37.

The spelling of 81252106813 in words is "eighty-one billion, two hundred fifty-two million, one hundred six thousand, eight hundred thirteen".