121771361557 has 2 divisors, whose sum is σ = 121771361558. Its totient is φ = 121771361556.

The previous prime is 121771361531. The next prime is 121771361561. The reversal of 121771361557 is 755163177121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77635234161 + 44136127396 = 278631^2 + 210086^2 .

It is a cyclic number.

It is not a de Polignac number, because 121771361557 - 2¹¹ = 121771359509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121771361567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60885680778 + 60885680779.

It is an arithmetic number, because the mean of its divisors is an integer number (60885680779).

Almost surely, 2^121771361557 is an apocalyptic number.

It is an amenable number.

121771361557 is a deficient number, since it is larger than the sum of its proper divisors (1).

121771361557 is an equidigital number, since it uses as much as digits as its factorization.

121771361557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 308700, while the sum is 46.

The spelling of 121771361557 in words is "one hundred twenty-one billion, seven hundred seventy-one million, three hundred sixty-one thousand, five hundred fifty-seven".