266381 has 2 divisors, whose sum is σ = 266382. Its totient is φ = 266380.

The previous prime is 266369. The next prime is 266401. The reversal of 266381 is 183662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 265225 + 1156 = 515^2 + 34^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-266381 is a prime.

It is a super-2 number, since 2×266381² = 141917674322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 266381.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 266381.

It is not a weakly prime, because it can be changed into another prime (266351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 133190 + 133191.

It is an arithmetic number, because the mean of its divisors is an integer number (133191).

2²⁶⁶³⁸¹ is an apocalyptic number.

It is an amenable number.

266381 is a deficient number, since it is larger than the sum of its proper divisors (1).

266381 is an equidigital number, since it uses as much as digits as its factorization.

266381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 266381 is about 516.1211098182. The cubic root of 266381 is about 64.3429667504.

It can be divided in two parts, 2663 and 81, that added together give a cube (2744 = 14³).

The spelling of 266381 in words is "two hundred sixty-six thousand, three hundred eighty-one".