71636421881 has 2 divisors, whose sum is σ = 71636421882. Its totient is φ = 71636421880.

The previous prime is 71636421863. The next prime is 71636421893. The reversal of 71636421881 is 18812463617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55267778281 + 16368643600 = 235091^2 + 127940^2 .

It is an emirp because it is prime and its reverse (18812463617) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71636421881 - 2⁶ = 71636421817 is a prime.

It is a super-2 number, since 2×71636421881² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71636421581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35818210940 + 35818210941.

It is an arithmetic number, because the mean of its divisors is an integer number (35818210941).

Almost surely, 2^71636421881 is an apocalyptic number.

It is an amenable number.

71636421881 is a deficient number, since it is larger than the sum of its proper divisors (1).

71636421881 is an equidigital number, since it uses as much as digits as its factorization.

71636421881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 387072, while the sum is 47.

The spelling of 71636421881 in words is "seventy-one billion, six hundred thirty-six million, four hundred twenty-one thousand, eight hundred eighty-one".