2154115121 has 4 divisors (see below), whose sum is σ = 2160507492. Its totient is φ = 2147722752.

The previous prime is 2154115111. The next prime is 2154115127. The reversal of 2154115121 is 1215114512.

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 505755121 + 1648360000 = 22489^2 + 40600^2 .

It is a cyclic number.

It is not a de Polignac number, because 2154115121 - 2¹⁰ = 2154114097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2154115127) 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, 3195680 + ... + 3196353.

It is an arithmetic number, because the mean of its divisors is an integer number (540126873).

Almost surely, 2^2154115121 is an apocalyptic number.

It is an amenable number.

2154115121 is a deficient number, since it is larger than the sum of its proper divisors (6392371).

2154115121 is an equidigital number, since it uses as much as digits as its factorization.

2154115121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6392370.

The product of its digits is 400, while the sum is 23.

The square root of 2154115121 is about 46412.4457554221. The cubic root of 2154115121 is about 1291.4858029900.

Adding to 2154115121 its reverse (1215114512), we get a palindrome (3369229633).

The spelling of 2154115121 in words is "two billion, one hundred fifty-four million, one hundred fifteen thousand, one hundred twenty-one".