121776807905 has 4 divisors (see below), whose sum is σ = 146132169492. Its totient is φ = 97421446320.

The previous prime is 121776807857. The next prime is 121776807907. The reversal of 121776807905 is 509708677121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 55854704896 + 65922103009 = 236336^2 + 256753^2 .

It is not a de Polignac number, because 121776807905 - 2²² = 121772613601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121776807907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12177680786 + ... + 12177680795.

It is an arithmetic number, because the mean of its divisors is an integer number (36533042373).

Almost surely, 2^121776807905 is an apocalyptic number.

It is an amenable number.

121776807905 is a deficient number, since it is larger than the sum of its proper divisors (24355361587).

121776807905 is an equidigital number, since it uses as much as digits as its factorization.

121776807905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24355361586.

The product of its (nonzero) digits is 1481760, while the sum is 53.

The spelling of 121776807905 in words is "one hundred twenty-one billion, seven hundred seventy-six million, eight hundred seven thousand, nine hundred five".