121235551 has 4 divisors (see below), whose sum is σ = 128367072. Its totient is φ = 114104032.

The previous prime is 121235549. The next prime is 121235563. The reversal of 121235551 is 155532121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155532121 = 73 ⋅2130577.

It is a cyclic number.

It is not a de Polignac number, because 121235551 - 2¹ = 121235549 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 (121235591) 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, 3565735 + ... + 3565768.

It is an arithmetic number, because the mean of its divisors is an integer number (32091768).

Almost surely, 2^121235551 is an apocalyptic number.

121235551 is a deficient number, since it is larger than the sum of its proper divisors (7131521).

121235551 is an equidigital number, since it uses as much as digits as its factorization.

121235551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7131520.

The product of its digits is 1500, while the sum is 25.

The square root of 121235551 is about 11010.7016579326. The cubic root of 121235551 is about 494.9294883067.

Adding to 121235551 its reverse (155532121), we get a palindrome (276767672).

It can be divided in two parts, 1212 and 35551, that added together give a palindrome (36763).

The spelling of 121235551 in words is "one hundred twenty-one million, two hundred thirty-five thousand, five hundred fifty-one".