121521155 has 8 divisors (see below), whose sum is σ = 166657632. Its totient is φ = 83328768.

The previous prime is 121521143. The next prime is 121521161. The reversal of 121521155 is 551125121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121521155 - 2²⁰ = 120472579 is a prime.

It is a super-2 number, since 2×121521155² = 29534782225068050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121521155.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1735982 + ... + 1736051.

It is an arithmetic number, because the mean of its divisors is an integer number (20832204).

Almost surely, 2^121521155 is an apocalyptic number.

121521155 is a deficient number, since it is larger than the sum of its proper divisors (45136477).

121521155 is an equidigital number, since it uses as much as digits as its factorization.

121521155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3472045.

The product of its digits is 500, while the sum is 23.

The square root of 121521155 is about 11023.6634110444. The cubic root of 121521155 is about 495.3178314565.

Adding to 121521155 its reverse (551125121), we get a palindrome (672646276).

The spelling of 121521155 in words is "one hundred twenty-one million, five hundred twenty-one thousand, one hundred fifty-five".