121377555 has 128 divisors (see below), whose sum is σ = 252887040. Its totient is φ = 54743040.

The previous prime is 121377551. The next prime is 121377593. The reversal of 121377555 is 555773121.

It is a happy number.

It is not a de Polignac number, because 121377555 - 2² = 121377551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121377551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1251267 + ... + 1251363.

It is an arithmetic number, because the mean of its divisors is an integer number (1975680).

Almost surely, 2^121377555 is an apocalyptic number.

121377555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

121377555 is an abundant number, since it is smaller than the sum of its proper divisors (131509485).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121377555 is a wasteful number, since it uses less digits than its factorization.

121377555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178 (or 172 counting only the distinct ones).

The product of its digits is 36750, while the sum is 36.

The square root of 121377555 is about 11017.1482244726. The cubic root of 121377555 is about 495.1226509661.

The spelling of 121377555 in words is "one hundred twenty-one million, three hundred seventy-seven thousand, five hundred fifty-five".