403681 has 2 divisors, whose sum is σ = 403682. Its totient is φ = 403680.

The previous prime is 403679. The next prime is 403687. The reversal of 403681 is 186304.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 360000 + 43681 = 600^2 + 209^2 .

It is a cyclic number.

It is not a de Polignac number, because 403681 - 2¹ = 403679 is a prime.

It is a super-2 number, since 2×403681² = 325916699522, which contains 22 as substring.

Together with 403679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (403687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201840 + 201841.

It is an arithmetic number, because the mean of its divisors is an integer number (201841).

2⁴⁰³⁶⁸¹ is an apocalyptic number.

It is an amenable number.

403681 is a deficient number, since it is larger than the sum of its proper divisors (1).

403681 is an equidigital number, since it uses as much as digits as its factorization.

403681 is an evil number, because the sum of its binary digits is even.

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

The square root of 403681 is about 635.3589536632. The cubic root of 403681 is about 73.9059555261.

Adding to 403681 its reverse (186304), we get a palindrome (589985).

It can be divided in two parts, 40 and 3681, that added together give a square (3721 = 61²).

The spelling of 403681 in words is "four hundred three thousand, six hundred eighty-one".