121321255553 has 4 divisors (see below), whose sum is σ = 123377548080. Its totient is φ = 119264963028.

The previous prime is 121321255547. The next prime is 121321255567. The reversal of 121321255553 is 355552123121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121321255553 - 2⁴ = 121321255537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121321255513) 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, 1028146175 + ... + 1028146292.

It is an arithmetic number, because the mean of its divisors is an integer number (30844387020).

Almost surely, 2^121321255553 is an apocalyptic number.

It is an amenable number.

121321255553 is a deficient number, since it is larger than the sum of its proper divisors (2056292527).

121321255553 is an equidigital number, since it uses as much as digits as its factorization.

121321255553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2056292526.

The product of its digits is 45000, while the sum is 35.

Adding to 121321255553 its reverse (355552123121), we get a palindrome (476873378674).

The spelling of 121321255553 in words is "one hundred twenty-one billion, three hundred twenty-one million, two hundred fifty-five thousand, five hundred fifty-three".