121716971557 has 2 divisors, whose sum is σ = 121716971558. Its totient is φ = 121716971556.

The previous prime is 121716971507. The next prime is 121716971591. The reversal of 121716971557 is 755179617121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87465696516 + 34251275041 = 295746^2 + 185071^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121716971557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121716971507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60858485778 + 60858485779.

It is an arithmetic number, because the mean of its divisors is an integer number (60858485779).

Almost surely, 2^121716971557 is an apocalyptic number.

It is an amenable number.

121716971557 is a deficient number, since it is larger than the sum of its proper divisors (1).

121716971557 is an equidigital number, since it uses as much as digits as its factorization.

121716971557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 926100, while the sum is 52.

The spelling of 121716971557 in words is "one hundred twenty-one billion, seven hundred sixteen million, nine hundred seventy-one thousand, five hundred fifty-seven".