121520551 has 4 divisors (see below), whose sum is σ = 121577112. Its totient is φ = 121463992.

The previous prime is 121520519. The next prime is 121520579. The reversal of 121520551 is 155025121.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 121520551 - 2⁵ = 121520519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121520501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24925 + ... + 29398.

It is an arithmetic number, because the mean of its divisors is an integer number (30394278).

Almost surely, 2^121520551 is an apocalyptic number.

121520551 is a deficient number, since it is larger than the sum of its proper divisors (56561).

121520551 is an equidigital number, since it uses as much as digits as its factorization.

121520551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56560.

The product of its (nonzero) digits is 500, while the sum is 22.

The square root of 121520551 is about 11023.6360153989. The cubic root of 121520551 is about 495.3170108245.

Adding to 121520551 its reverse (155025121), we get a palindrome (276545672).

The spelling of 121520551 in words is "one hundred twenty-one million, five hundred twenty thousand, five hundred fifty-one".