121561022777 has 2 divisors, whose sum is σ = 121561022778. Its totient is φ = 121561022776.

The previous prime is 121561022663. The next prime is 121561022857. The reversal of 121561022777 is 777220165121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81051812416 + 40509210361 = 284696^2 + 201269^2 .

It is a cyclic number.

It is not a de Polignac number, because 121561022777 - 2¹² = 121561018681 is a prime.

It is not a weakly prime, because it can be changed into another prime (121561022377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60780511388 + 60780511389.

It is an arithmetic number, because the mean of its divisors is an integer number (60780511389).

Almost surely, 2^121561022777 is an apocalyptic number.

It is an amenable number.

121561022777 is a deficient number, since it is larger than the sum of its proper divisors (1).

121561022777 is an equidigital number, since it uses as much as digits as its factorization.

121561022777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82320, while the sum is 41.

Adding to 121561022777 its reverse (777220165121), we get a palindrome (898781187898).

The spelling of 121561022777 in words is "one hundred twenty-one billion, five hundred sixty-one million, twenty-two thousand, seven hundred seventy-seven".