121755421757 has 4 divisors (see below), whose sum is σ = 121773576540. Its totient is φ = 121737266976.

The previous prime is 121755421741. The next prime is 121755421759. The reversal of 121755421757 is 757124557121.

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 32453662201 + 89301759556 = 180149^2 + 298834^2 .

It is a cyclic number.

It is not a de Polignac number, because 121755421757 - 2⁴ = 121755421741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121755421759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9067328 + ... + 9080745.

It is an arithmetic number, because the mean of its divisors is an integer number (30443394135).

Almost surely, 2^121755421757 is an apocalyptic number.

It is an amenable number.

121755421757 is a deficient number, since it is larger than the sum of its proper divisors (18154783).

121755421757 is an equidigital number, since it uses as much as digits as its factorization.

121755421757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18154782.

The product of its digits is 686000, while the sum is 47.

Adding to 121755421757 its reverse (757124557121), we get a palindrome (878879978878).

The spelling of 121755421757 in words is "one hundred twenty-one billion, seven hundred fifty-five million, four hundred twenty-one thousand, seven hundred fifty-seven".