121405155 has 32 divisors (see below), whose sum is σ = 213373440. Its totient is φ = 58671360.

The previous prime is 121405147. The next prime is 121405169. The reversal of 121405155 is 551504121.

It is not a de Polignac number, because 121405155 - 2³ = 121405147 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2706 + ... + 15815.

It is an arithmetic number, because the mean of its divisors is an integer number (6667920).

Almost surely, 2^121405155 is an apocalyptic number.

121405155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

121405155 is a deficient number, since it is larger than the sum of its proper divisors (91968285).

121405155 is a wasteful number, since it uses less digits than its factorization.

121405155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18571.

The product of its (nonzero) digits is 1000, while the sum is 24.

The square root of 121405155 is about 11018.4007460248. The cubic root of 121405155 is about 495.1601767110.

Adding to 121405155 its reverse (551504121), we get a palindrome (672909276).

The spelling of 121405155 in words is "one hundred twenty-one million, four hundred five thousand, one hundred fifty-five".