2155381 has 2 divisors, whose sum is σ = 2155382. Its totient is φ = 2155380.

The previous prime is 2155333. The next prime is 2155393. The reversal of 2155381 is 1835512.

It is a happy number.

2155381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1988100 + 167281 = 1410^2 + 409^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155381 - 2⁷ = 2155253 is a prime.

It is a super-2 number, since 2×2155381² = 9291334510322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2155781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077690 + 1077691.

It is an arithmetic number, because the mean of its divisors is an integer number (1077691).

2^2155381 is an apocalyptic number.

It is an amenable number.

2155381 is a deficient number, since it is larger than the sum of its proper divisors (1).

2155381 is an equidigital number, since it uses as much as digits as its factorization.

2155381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1200, while the sum is 25.

The square root of 2155381 is about 1468.1215889701. The cubic root of 2155381 is about 129.1738736642.

The spelling of 2155381 in words is "two million, one hundred fifty-five thousand, three hundred eighty-one".