400023 has 18 divisors (see below), whose sum is σ = 628056. Its totient is φ = 245232.

The previous prime is 400009. The next prime is 400031. The reversal of 400023 is 320004.

It is not a de Polignac number, because 400023 - 2¹⁶ = 334487 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 399978 and 400014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400033) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1390 + ... + 1652.

It is an arithmetic number, because the mean of its divisors is an integer number (34892).

2⁴⁰⁰⁰²³ is an apocalyptic number.

400023 is a deficient number, since it is larger than the sum of its proper divisors (228033).

400023 is a wasteful number, since it uses less digits than its factorization.

400023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 9.

The square root of 400023 is about 632.4737148688. The cubic root of 400023 is about 73.6820421578.

Adding to 400023 its reverse (320004), we get a palindrome (720027).

The spelling of 400023 in words is "four hundred thousand, twenty-three", and thus it is an iban number.