403 has 4 divisors (see below), whose sum is σ = 448. Its totient is φ = 360.

The previous prime is 401. The next prime is 409. The reversal of 403 is 304.

403 is nontrivially palindromic in base 2.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 403 - 2^{1} = 401 is a prime.

It is a magnanimous number.

It is a Duffinian number.

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

It is not an unprimeable number, because it can be changed into a prime (401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3 + ... + 28.

It is an arithmetic number, because the mean of its divisors is an integer number (112).

403 is the 13-th heptagonal number.

403 is a deficient number, since it is larger than the sum of its proper divisors (45).

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

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

The sum of its prime factors is 44.

The product of its (nonzero) digits is 12, while the sum is 7.

The square root of 403 is about 20.0748598999. The cubic root of 403 is about 7.3864372953.

Adding to 403 its reverse (304), we get a palindrome (707).

Subtracting from 403 its reverse (304), we obtain a palindrome (99).

It can be divided in two parts, 40 and 3, that multiplied together give a triangular number (120 = T_{15}).

The spelling of 403 in words is "four hundred three", and thus it is an aban number and an iban number.

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