2156813 has 2 divisors, whose sum is σ = 2156814. Its totient is φ = 2156812.

The previous prime is 2156809. The next prime is 2156839. The reversal of 2156813 is 3186512.

It is an a-pointer prime, because the next prime (2156839) can be obtained adding 2156813 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1387684 + 769129 = 1178^2 + 877^2 .

It is a cyclic number.

It is not a de Polignac number, because 2156813 - 2² = 2156809 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2156873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078406 + 1078407.

It is an arithmetic number, because the mean of its divisors is an integer number (1078407).

2^2156813 is an apocalyptic number.

It is an amenable number.

2156813 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156813 is an equidigital number, since it uses as much as digits as its factorization.

2156813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 26.

The square root of 2156813 is about 1468.6092060177. The cubic root of 2156813 is about 129.2024743365.

The spelling of 2156813 in words is "two million, one hundred fifty-six thousand, eight hundred thirteen".