1340642665 has 4 divisors (see below), whose sum is σ = 1608771204. Its totient is φ = 1072514128.

The previous prime is 1340642657. The next prime is 1340642669. The reversal of 1340642665 is 5662460431.

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 145419481 + 1195223184 = 12059^2 + 34572^2 .

It is a cyclic number.

It is not a de Polignac number, because 1340642665 - 2³ = 1340642657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1340642669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134064262 + ... + 134064271.

It is an arithmetic number, because the mean of its divisors is an integer number (402192801).

Almost surely, 2^1340642665 is an apocalyptic number.

It is an amenable number.

1340642665 is a deficient number, since it is larger than the sum of its proper divisors (268128539).

1340642665 is an equidigital number, since it uses as much as digits as its factorization.

1340642665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268128538.

The product of its (nonzero) digits is 103680, while the sum is 37.

The square root of 1340642665 is about 36614.7875181599. The cubic root of 1340642665 is about 1102.6499923620.

The spelling of 1340642665 in words is "one billion, three hundred forty million, six hundred forty-two thousand, six hundred sixty-five".