71520913181 has 2 divisors, whose sum is σ = 71520913182. Its totient is φ = 71520913180.

The previous prime is 71520913171. The next prime is 71520913241. The reversal of 71520913181 is 18131902517.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53754422500 + 17766490681 = 231850^2 + 133291^2 .

It is a cyclic number.

It is not a de Polignac number, because 71520913181 - 2³⁰ = 70447171357 is a prime.

It is a super-2 number, since 2×71520913181² (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 (71520913111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35760456590 + 35760456591.

It is an arithmetic number, because the mean of its divisors is an integer number (35760456591).

Almost surely, 2^71520913181 is an apocalyptic number.

It is an amenable number.

71520913181 is a deficient number, since it is larger than the sum of its proper divisors (1).

71520913181 is an equidigital number, since it uses as much as digits as its factorization.

71520913181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 38.

The spelling of 71520913181 in words is "seventy-one billion, five hundred twenty million, nine hundred thirteen thousand, one hundred eighty-one".