1252787665 has 4 divisors (see below), whose sum is σ = 1503345204. Its totient is φ = 1002230128.

The previous prime is 1252787611. The next prime is 1252787693. The reversal of 1252787665 is 5667872521.

It is a happy number.

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 830361856 + 422425809 = 28816^2 + 20553^2 .

It is a cyclic number.

It is not a de Polignac number, because 1252787665 - 2¹⁷ = 1252656593 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125278762 + ... + 125278771.

It is an arithmetic number, because the mean of its divisors is an integer number (375836301).

Almost surely, 2^1252787665 is an apocalyptic number.

It is an amenable number.

1252787665 is a deficient number, since it is larger than the sum of its proper divisors (250557539).

1252787665 is an equidigital number, since it uses as much as digits as its factorization.

1252787665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250557538.

The product of its digits is 1411200, while the sum is 49.

The square root of 1252787665 is about 35394.7406403833. The cubic root of 1252787665 is about 1078.0175294288.

The spelling of 1252787665 in words is "one billion, two hundred fifty-two million, seven hundred eighty-seven thousand, six hundred sixty-five".