1299465665 has 4 divisors (see below), whose sum is σ = 1559358804. Its totient is φ = 1039572528.

The previous prime is 1299465649. The next prime is 1299465701. The reversal of 1299465665 is 5665649921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5665649921 = 47 ⋅120545743.

It can be written as a sum of positive squares in 2 ways, for example, as 259467664 + 1039998001 = 16108^2 + 32249^2 .

It is a cyclic number.

It is not a de Polignac number, because 1299465665 - 2⁴ = 1299465649 is a prime.

It is a super-2 number, since 2×1299465665² = 3377222029027784450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129946562 + ... + 129946571.

It is an arithmetic number, because the mean of its divisors is an integer number (389839701).

Almost surely, 2^1299465665 is an apocalyptic number.

It is an amenable number.

1299465665 is a deficient number, since it is larger than the sum of its proper divisors (259893139).

1299465665 is an equidigital number, since it uses as much as digits as its factorization.

1299465665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259893138.

The product of its digits is 3499200, while the sum is 53.

The square root of 1299465665 is about 36048.1020998332. The cubic root of 1299465665 is about 1091.2433319499.

The spelling of 1299465665 in words is "one billion, two hundred ninety-nine million, four hundred sixty-five thousand, six hundred sixty-five".