121261555 has 4 divisors (see below), whose sum is σ = 145513872. Its totient is φ = 97009240.

The previous prime is 121261549. The next prime is 121261573. The reversal of 121261555 is 555162121.

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

It is not a de Polignac number, because 121261555 - 2⁵ = 121261523 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 12126151 + ... + 12126160.

It is an arithmetic number, because the mean of its divisors is an integer number (36378468).

Almost surely, 2^121261555 is an apocalyptic number.

121261555 is a deficient number, since it is larger than the sum of its proper divisors (24252317).

121261555 is an equidigital number, since it uses as much as digits as its factorization.

121261555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24252316.

The product of its digits is 3000, while the sum is 28.

The square root of 121261555 is about 11011.8824457946. The cubic root of 121261555 is about 494.9648718397.

The spelling of 121261555 in words is "one hundred twenty-one million, two hundred sixty-one thousand, five hundred fifty-five".