1265163101 has 4 divisors (see below), whose sum is σ = 1266080604. Its totient is φ = 1264245600.

The previous prime is 1265163083. The next prime is 1265163149. The reversal of 1265163101 is 1013615621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1013615621 = 617 ⋅1642813.

It can be written as a sum of positive squares in 2 ways, for example, as 992880100 + 272283001 = 31510^2 + 16501^2 .

It is a cyclic number.

It is not a de Polignac number, because 1265163101 - 2¹⁸ = 1264900957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265163161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 456680 + ... + 459441.

It is an arithmetic number, because the mean of its divisors is an integer number (316520151).

Almost surely, 2^1265163101 is an apocalyptic number.

It is an amenable number.

1265163101 is a deficient number, since it is larger than the sum of its proper divisors (917503).

1265163101 is an equidigital number, since it uses as much as digits as its factorization.

1265163101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917502.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 1265163101 is about 35569.1312938621. The cubic root of 1265163101 is about 1081.5555718654. Note that the first 4 decimals are identical.

Adding to 1265163101 its reverse (1013615621), we get a palindrome (2278778722).

The spelling of 1265163101 in words is "one billion, two hundred sixty-five million, one hundred sixty-three thousand, one hundred one".