121206557 has 4 divisors (see below), whose sum is σ = 121276320. Its totient is φ = 121136796.

The previous prime is 121206523. The next prime is 121206563. The reversal of 121206557 is 755602121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 755602121 = 127 ⋅5949623.

It is a cyclic number.

It is not a de Polignac number, because 121206557 - 2¹⁰ = 121205533 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 (121206517) 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, 32207 + ... + 35772.

It is an arithmetic number, because the mean of its divisors is an integer number (30319080).

Almost surely, 2^121206557 is an apocalyptic number.

It is an amenable number.

121206557 is a deficient number, since it is larger than the sum of its proper divisors (69763).

121206557 is an equidigital number, since it uses as much as digits as its factorization.

121206557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69762.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 121206557 is about 11009.3849510316. The cubic root of 121206557 is about 494.8900303272.

Adding to 121206557 its reverse (755602121), we get a palindrome (876808678).

The spelling of 121206557 in words is "one hundred twenty-one million, two hundred six thousand, five hundred fifty-seven".