406381 has 2 divisors, whose sum is σ = 406382. Its totient is φ = 406380.

The previous prime is 406361. The next prime is 406397. The reversal of 406381 is 183604.

406381 = T₅₁₉ + T₅₂₀ + T₅₂₁.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217156 + 189225 = 466^2 + 435^2 .

It is a cyclic number.

It is not a de Polignac number, because 406381 - 2⁵ = 406349 is a prime.

It is a super-2 number, since 2×406381² = 330291034322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (406331) 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, 203190 + 203191.

It is an arithmetic number, because the mean of its divisors is an integer number (203191).

2⁴⁰⁶³⁸¹ is an apocalyptic number.

406381 is the 521-st centered triangular number.

It is an amenable number.

406381 is a deficient number, since it is larger than the sum of its proper divisors (1).

406381 is an equidigital number, since it uses as much as digits as its factorization.

406381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 406381 is about 637.4801957708. The cubic root of 406381 is about 74.0703616133.

Adding to 406381 its reverse (183604), we get a palindrome (589985).

It can be divided in two parts, 406 and 381, that added together give a palindrome (787).

The spelling of 406381 in words is "four hundred six thousand, three hundred eighty-one".