400643 has 2 divisors, whose sum is σ = 400644. Its totient is φ = 400642.

The previous prime is 400619. The next prime is 400651. The reversal of 400643 is 346004.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 400643 - 2⁶ = 400579 is a prime.

It is not a weakly prime, because it can be changed into another prime (400243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200321 + 200322.

It is an arithmetic number, because the mean of its divisors is an integer number (200322).

2⁴⁰⁰⁶⁴³ is an apocalyptic number.

400643 is a deficient number, since it is larger than the sum of its proper divisors (1).

400643 is an equidigital number, since it uses as much as digits as its factorization.

400643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 400643 is about 632.9636640440. The cubic root of 400643 is about 73.7200893743.

Adding to 400643 its reverse (346004), we get a palindrome (746647).

The spelling of 400643 in words is "four hundred thousand, six hundred forty-three".