1491 has 8 divisors (see below), whose sum is σ = 2304. Its totient is φ = 840.

The previous prime is 1489. The next prime is 1493. The reversal of 1491 is 1941.

1491 = 3^{2} + 4^{2} + ... + 16^{2}.

1491 is nontrivially palindromic in base 14 and base 15.

1491 is an esthetic number in base 14, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (1489) and next prime (1493).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1491 - 2^{1} = 1489 is a prime.

1491 is an undulating number in base 14 and base 15.

1491 is a lucky number.

It is a plaindrome in base 11.

It is a nialpdrome in base 12.

It is a self number, because there is not a number *n* which added to its sum of digits gives 1491.

It is an inconsummate number, since it does not exist a number *n* which divided by its sum of digits gives 1491.

It is not an unprimeable number, because it can be changed into a prime (1493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15 + ... + 56.

It is an arithmetic number, because the mean of its divisors is an integer number (288).

1491 is the 21-st nonagonal number.

1491 is a deficient number, since it is larger than the sum of its proper divisors (813).

1491 is an equidigital number, since it uses as much as digits as its factorization.

1491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81.

The product of its digits is 36, while the sum is 15.

The square root of 1491 is about 38.6134691526. The cubic root of 1491 is about 11.4242021989.

It can be divided in two parts, 14 and 91, that added together give a triangular number (105 = T_{14}).

The spelling of 1491 in words is "one thousand, four hundred ninety-one".

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