71945138261 has 2 divisors, whose sum is σ = 71945138262. Its totient is φ = 71945138260.

The previous prime is 71945138231. The next prime is 71945138327. The reversal of 71945138261 is 16283154917.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51633472900 + 20311665361 = 227230^2 + 142519^2 .

It is a cyclic number.

It is not a de Polignac number, because 71945138261 - 2⁶ = 71945138197 is a prime.

It is a super-2 number, since 2×71945138261² (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 (71945138231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35972569130 + 35972569131.

It is an arithmetic number, because the mean of its divisors is an integer number (35972569131).

Almost surely, 2^71945138261 is an apocalyptic number.

It is an amenable number.

71945138261 is a deficient number, since it is larger than the sum of its proper divisors (1).

71945138261 is an equidigital number, since it uses as much as digits as its factorization.

71945138261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 47.

The spelling of 71945138261 in words is "seventy-one billion, nine hundred forty-five million, one hundred thirty-eight thousand, two hundred sixty-one".