121555211603 has 4 divisors (see below), whose sum is σ = 138920241840. Its totient is φ = 104190181368.

The previous prime is 121555211599. The next prime is 121555211621. The reversal of 121555211603 is 306112555121.

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

It is not a de Polignac number, because 121555211603 - 2² = 121555211599 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121555211603.

It is not an unprimeable number, because it can be changed into a prime (121555211633) 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, 8682515108 + ... + 8682515121.

It is an arithmetic number, because the mean of its divisors is an integer number (34730060460).

Almost surely, 2^121555211603 is an apocalyptic number.

121555211603 is a deficient number, since it is larger than the sum of its proper divisors (17365030237).

121555211603 is an equidigital number, since it uses as much as digits as its factorization.

121555211603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17365030236.

The product of its (nonzero) digits is 9000, while the sum is 32.

Adding to 121555211603 its reverse (306112555121), we get a palindrome (427667766724).

The spelling of 121555211603 in words is "one hundred twenty-one billion, five hundred fifty-five million, two hundred eleven thousand, six hundred three".