213881 has 2 divisors, whose sum is σ = 213882. Its totient is φ = 213880.

The previous prime is 213859. The next prime is 213887. The reversal of 213881 is 188312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 133225 + 80656 = 365^2 + 284^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213881 is a prime.

It is a super-2 number, since 2×213881² = 91490164322, which contains 22 as substring.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 213881.

It is not a weakly prime, because it can be changed into another prime (213887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106940 + 106941.

It is an arithmetic number, because the mean of its divisors is an integer number (106941).

2²¹³⁸⁸¹ is an apocalyptic number.

It is an amenable number.

213881 is a deficient number, since it is larger than the sum of its proper divisors (1).

213881 is an equidigital number, since it uses as much as digits as its factorization.

213881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 23.

The square root of 213881 is about 462.4727018971. The cubic root of 213881 is about 59.8031511783.

The spelling of 213881 in words is "two hundred thirteen thousand, eight hundred eighty-one".