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401 is a prime number

401 has 2 divisors, whose sum is σ = 402. Its totient is φ = 400.

The previous prime is 397. The next prime is 409. The reversal of 401 is 104.

401 is nontrivially palindromic in base 16.

It is a Cunningham number, because it is equal to 202+1.

401 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 400 + 1 = 20^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 401 - 22 = 397 is a prime.

It is a Chen prime.

It is a tetranacci number.

It is a magnanimous number.

401 is an undulating number in base 16.

It is a plaindrome in base 7, base 11, base 13 and base 15.

It is a nialpdrome in base 8.

It is not a weakly prime, because it can be changed into another prime (409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200 + 201.

It is an arithmetic number, because the mean of its divisors is an integer number (201).

It is an amenable number.

401 is a deficient number, since it is larger than the sum of its proper divisors (1).

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

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

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 401 is about 20.0249843945. The cubic root of 401 is about 7.3741979402.

Adding to 401 its reverse (104), we get a palindrome (505).

The spelling of 401 in words is "four hundred one", and thus it is an aban number and an iban number.