121520553 has 16 divisors (see below), whose sum is σ = 202008576. Its totient is φ = 63127440.

The previous prime is 121520519. The next prime is 121520579. The reversal of 121520553 is 355025121.

It is a happy number.

It is not a de Polignac number, because 121520553 - 2⁶ = 121520489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121520053) 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, 262801 + ... + 263262.

It is an arithmetic number, because the mean of its divisors is an integer number (12625536).

Almost surely, 2^121520553 is an apocalyptic number.

It is an amenable number.

121520553 is a deficient number, since it is larger than the sum of its proper divisors (80488023).

121520553 is a wasteful number, since it uses less digits than its factorization.

121520553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526084.

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 121520553 is about 11023.6361061131. The cubic root of 121520553 is about 495.3170135418.

Adding to 121520553 its reverse (355025121), we get a palindrome (476545674).

The spelling of 121520553 in words is "one hundred twenty-one million, five hundred twenty thousand, five hundred fifty-three".