400144021 has 4 divisors (see below), whose sum is σ = 400511212. Its totient is φ = 399776832.

The previous prime is 400143929. The next prime is 400144049. The reversal of 400144021 is 120441004.

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 262926225 + 137217796 = 16215^2 + 11714^2 .

It is a cyclic number.

It is not a de Polignac number, because 400144021 - 2²⁵ = 366589589 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400143986 and 400144004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400144061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181956 + ... + 184141.

It is an arithmetic number, because the mean of its divisors is an integer number (100127803).

Almost surely, 2^400144021 is an apocalyptic number.

It is an amenable number.

400144021 is a deficient number, since it is larger than the sum of its proper divisors (367191).

400144021 is a wasteful number, since it uses less digits than its factorization.

400144021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367190.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 400144021 is about 20003.6002009638. The cubic root of 400144021 is about 736.8947187672.

Adding to 400144021 its reverse (120441004), we get a palindrome (520585025).

The spelling of 400144021 in words is "four hundred million, one hundred forty-four thousand, twenty-one".