1281641 has 4 divisors (see below), whose sum is σ = 1286484. Its totient is φ = 1276800.

The previous prime is 1281587. The next prime is 1281649. The reversal of 1281641 is 1461821.

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 648025 + 633616 = 805^2 + 796^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1281641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1281649) 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 3 ways as a sum of consecutive naturals, for example, 2000 + ... + 2561.

It is an arithmetic number, because the mean of its divisors is an integer number (321621).

2^1281641 is an apocalyptic number.

It is an amenable number.

1281641 is a deficient number, since it is larger than the sum of its proper divisors (4843).

1281641 is an equidigital number, since it uses as much as digits as its factorization.

1281641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4842.

The product of its digits is 384, while the sum is 23.

The square root of 1281641 is about 1132.0958439991. The cubic root of 1281641 is about 108.6230844255.

It can be divided in two parts, 1281 and 641, that multiplied together give a triangular number (821121 = T₁₂₈₁).

The spelling of 1281641 in words is "one million, two hundred eighty-one thousand, six hundred forty-one".