121021155 has 16 divisors (see below), whose sum is σ = 215148960. Its totient is φ = 64544544.

The previous prime is 121021151. The next prime is 121021157. The reversal of 121021155 is 551120121.

It is not a de Polignac number, because 121021155 - 2² = 121021151 is a prime.

It is a super-2 number, since 2×121021155² = 29292239915068050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (121021151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 448092 + ... + 448361.

It is an arithmetic number, because the mean of its divisors is an integer number (13446810).

Almost surely, 2^121021155 is an apocalyptic number.

121021155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

121021155 is a deficient number, since it is larger than the sum of its proper divisors (94127805).

121021155 is an equidigital number, since it uses as much as digits as its factorization.

121021155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 896467 (or 896461 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 18.

The square root of 121021155 is about 11000.9615488829. The cubic root of 121021155 is about 494.6375675707.

Adding to 121021155 its reverse (551120121), we get a palindrome (672141276).

The spelling of 121021155 in words is "one hundred twenty-one million, twenty-one thousand, one hundred fifty-five".