400221 has 18 divisors (see below), whose sum is σ = 610142. Its totient is φ = 262440.
The previous prime is 400217. The next prime is 400237. The reversal of 400221 is 122004.
It can be written as a sum of positive squares in only one way, i.e., 236196 + 164025 = 486^2 + 405^2 .
It is not a de Polignac number, because 400221 - 22 = 400217 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (400261) 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 17 ways as a sum of consecutive naturals, for example, 6531 + ... + 6591.
2400221 is an apocalyptic number.
It is an amenable number.
400221 is a deficient number, since it is larger than the sum of its proper divisors (209921).
400221 is an frugal number, since it uses more digits than its factorization.
400221 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 85 (or 64 counting only the distinct ones).
The product of its (nonzero) digits is 16, while the sum is 9.
The square root of 400221 is about 632.6302237484. The cubic root of 400221 is about 73.6941969905.
Adding to 400221 its reverse (122004), we get a palindrome (522225).
The spelling of 400221 in words is "four hundred thousand, two hundred twenty-one", and thus it is an iban number.
• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.066 sec. • engine limits •