71298787981 has 2 divisors, whose sum is σ = 71298787982. Its totient is φ = 71298787980.

The previous prime is 71298787961. The next prime is 71298787997. The reversal of 71298787981 is 18978789217.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71294340100 + 4447881 = 267010^2 + 2109^2 .

It is a cyclic number.

It is not a de Polignac number, because 71298787981 - 2¹⁷ = 71298656909 is a prime.

It is a super-2 number, since 2×71298787981² (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 (71298787961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35649393990 + 35649393991.

It is an arithmetic number, because the mean of its divisors is an integer number (35649393991).

Almost surely, 2^71298787981 is an apocalyptic number.

It is an amenable number.

71298787981 is a deficient number, since it is larger than the sum of its proper divisors (1).

71298787981 is an equidigital number, since it uses as much as digits as its factorization.

71298787981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28449792, while the sum is 67.

The spelling of 71298787981 in words is "seventy-one billion, two hundred ninety-eight million, seven hundred eighty-seven thousand, nine hundred eighty-one".