2172154121 has 2 divisors, whose sum is σ = 2172154122. Its totient is φ = 2172154120.

The previous prime is 2172154093. The next prime is 2172154163. The reversal of 2172154121 is 1214512712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1832268025 + 339886096 = 42805^2 + 18436^2 .

It is a cyclic number.

It is not a de Polignac number, because 2172154121 - 2²² = 2167959817 is a prime.

It is not a weakly prime, because it can be changed into another prime (2172054121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1086077060 + 1086077061.

It is an arithmetic number, because the mean of its divisors is an integer number (1086077061).

Almost surely, 2^2172154121 is an apocalyptic number.

It is an amenable number.

2172154121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2172154121 is an equidigital number, since it uses as much as digits as its factorization.

2172154121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1120, while the sum is 26.

The square root of 2172154121 is about 46606.3742528852. The cubic root of 2172154121 is about 1295.0808416908.

Adding to 2172154121 its reverse (1214512712), we get a palindrome (3386666833).

The spelling of 2172154121 in words is "two billion, one hundred seventy-two million, one hundred fifty-four thousand, one hundred twenty-one".