400621 has 4 divisors (see below), whose sum is σ = 431452. Its totient is φ = 369792.

The previous prime is 400619. The next prime is 400643. The reversal of 400621 is 126004.

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 34596 + 366025 = 186^2 + 605^2 .

It is a cyclic number.

It is not a de Polignac number, because 400621 - 2¹ = 400619 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 30817 = 400621 / (4 + 0 + 0 + 6 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15396 + ... + 15421.

It is an arithmetic number, because the mean of its divisors is an integer number (107863).

2⁴⁰⁰⁶²¹ is an apocalyptic number.

It is an amenable number.

400621 is a deficient number, since it is larger than the sum of its proper divisors (30831).

400621 is a wasteful number, since it uses less digits than its factorization.

400621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30830.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 400621 is about 632.9462852407. The cubic root of 400621 is about 73.7187399837.

Adding to 400621 its reverse (126004), we get a palindrome (526625).

The spelling of 400621 in words is "four hundred thousand, six hundred twenty-one".