121439781977 has 2 divisors, whose sum is σ = 121439781978. Its totient is φ = 121439781976.

The previous prime is 121439781959. The next prime is 121439781989. The reversal of 121439781977 is 779187934121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120134332816 + 1305449161 = 346604^2 + 36131^2 .

It is a cyclic number.

It is not a de Polignac number, because 121439781977 - 2¹⁴ = 121439765593 is a prime.

It is not a weakly prime, because it can be changed into another prime (121439781997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60719890988 + 60719890989.

It is an arithmetic number, because the mean of its divisors is an integer number (60719890989).

Almost surely, 2^121439781977 is an apocalyptic number.

It is an amenable number.

121439781977 is a deficient number, since it is larger than the sum of its proper divisors (1).

121439781977 is an equidigital number, since it uses as much as digits as its factorization.

121439781977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5334336, while the sum is 59.

The spelling of 121439781977 in words is "one hundred twenty-one billion, four hundred thirty-nine million, seven hundred eighty-one thousand, nine hundred seventy-seven".