85644311381 has 2 divisors, whose sum is σ = 85644311382. Its totient is φ = 85644311380.

The previous prime is 85644311369. The next prime is 85644311387. The reversal of 85644311381 is 18311344658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70166712100 + 15477599281 = 264890^2 + 124409^2 .

It is a cyclic number.

It is not a de Polignac number, because 85644311381 - 2²⁶ = 85577202517 is a prime.

It is a super-2 number, since 2×85644311381² (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 (85644311387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42822155690 + 42822155691.

It is an arithmetic number, because the mean of its divisors is an integer number (42822155691).

Almost surely, 2^85644311381 is an apocalyptic number.

It is an amenable number.

85644311381 is a deficient number, since it is larger than the sum of its proper divisors (1).

85644311381 is an equidigital number, since it uses as much as digits as its factorization.

85644311381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 276480, while the sum is 44.

The spelling of 85644311381 in words is "eighty-five billion, six hundred forty-four million, three hundred eleven thousand, three hundred eighty-one".