121553213 has 4 divisors (see below), whose sum is σ = 128703420. Its totient is φ = 114403008.

The previous prime is 121553191. The next prime is 121553219. The reversal of 121553213 is 312355121.

It is a happy number.

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 100741369 + 20811844 = 10037^2 + 4562^2 .

It is a cyclic number.

It is not a de Polignac number, because 121553213 - 2⁶ = 121553149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121553219) 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, 3575078 + ... + 3575111.

It is an arithmetic number, because the mean of its divisors is an integer number (32175855).

Almost surely, 2^121553213 is an apocalyptic number.

It is an amenable number.

121553213 is a deficient number, since it is larger than the sum of its proper divisors (7150207).

121553213 is an equidigital number, since it uses as much as digits as its factorization.

121553213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7150206.

The product of its digits is 900, while the sum is 23.

The square root of 121553213 is about 11025.1173689898. The cubic root of 121553213 is about 495.3613835522.

The spelling of 121553213 in words is "one hundred twenty-one million, five hundred fifty-three thousand, two hundred thirteen".