121520557 has 4 divisors (see below), whose sum is σ = 121543740. Its totient is φ = 121497376.

The previous prime is 121520519. The next prime is 121520579. The reversal of 121520557 is 755025121.

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

It can be written as a sum of positive squares in 2 ways, for example, as 97891236 + 23629321 = 9894^2 + 4861^2 .

It is a cyclic number.

It is not a de Polignac number, because 121520557 - 2¹⁹ = 120996269 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 (121520587) 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, 423 + ... + 15595.

It is an arithmetic number, because the mean of its divisors is an integer number (30385935).

Almost surely, 2^121520557 is an apocalyptic number.

It is an amenable number.

121520557 is a deficient number, since it is larger than the sum of its proper divisors (23183).

121520557 is an equidigital number, since it uses as much as digits as its factorization.

121520557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23182.

The product of its (nonzero) digits is 3500, while the sum is 28.

The square root of 121520557 is about 11023.6362875414. The cubic root of 121520557 is about 495.3170189764.

Adding to 121520557 its reverse (755025121), we get a palindrome (876545678).

The spelling of 121520557 in words is "one hundred twenty-one million, five hundred twenty thousand, five hundred fifty-seven".