400203421 has 4 divisors (see below), whose sum is σ = 402889500. Its totient is φ = 397517344.

The previous prime is 400203407. The next prime is 400203437. The reversal of 400203421 is 124302004.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 156500100 + 243703321 = 12510^2 + 15611^2 .

It is a cyclic number.

It is not a de Polignac number, because 400203421 - 2⁵ = 400203389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400203395 and 400203404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400203481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1342816 + ... + 1343113.

It is an arithmetic number, because the mean of its divisors is an integer number (100722375).

Almost surely, 2^400203421 is an apocalyptic number.

It is an amenable number.

400203421 is a deficient number, since it is larger than the sum of its proper divisors (2686079).

400203421 is a wasteful number, since it uses less digits than its factorization.

400203421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2686078.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 400203421 is about 20005.0848786002. The cubic root of 400203421 is about 736.9311801230.

Adding to 400203421 its reverse (124302004), we get a palindrome (524505425).

The spelling of 400203421 in words is "four hundred million, two hundred three thousand, four hundred twenty-one".