1290665 has 8 divisors (see below), whose sum is σ = 1555848. Its totient is φ = 1027840.

The previous prime is 1290659. The next prime is 1290673. The reversal of 1290665 is 5660921.

It can be written as a sum of positive squares in 4 ways, for example, as 215296 + 1075369 = 464^2 + 1037^2 .

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

It is not a de Polignac number, because 1290665 - 2⁴ = 1290649 is a prime.

It is a super-2 number, since 2×1290665² = 3331632284450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1025 + ... + 1905.

It is an arithmetic number, because the mean of its divisors is an integer number (194481).

2^1290665 is an apocalyptic number.

It is an amenable number.

1290665 is a deficient number, since it is larger than the sum of its proper divisors (265183).

1290665 is an equidigital number, since it uses as much as digits as its factorization.

1290665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1179.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 1290665 is about 1136.0743813677. The cubic root of 1290665 is about 108.8774258299.

The spelling of 1290665 in words is "one million, two hundred ninety thousand, six hundred sixty-five".