400661221 has 4 divisors (see below), whose sum is σ = 400711852. Its totient is φ = 400610592.

The previous prime is 400661207. The next prime is 400661263. The reversal of 400661221 is 122166004.

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 399440196 + 1221025 = 19986^2 + 1105^2 .

It is a cyclic number.

It is not a de Polignac number, because 400661221 - 2¹¹ = 400659173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400661192 and 400661201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400661281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10590 + ... + 30223.

It is an arithmetic number, because the mean of its divisors is an integer number (100177963).

Almost surely, 2^400661221 is an apocalyptic number.

It is an amenable number.

400661221 is a deficient number, since it is larger than the sum of its proper divisors (50631).

400661221 is an equidigital number, since it uses as much as digits as its factorization.

400661221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50630.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 400661221 is about 20016.5236991841. The cubic root of 400661221 is about 737.2120693892.

The spelling of 400661221 in words is "four hundred million, six hundred sixty-one thousand, two hundred twenty-one".