1265725779 has 4 divisors (see below), whose sum is σ = 1687634376. Its totient is φ = 843817184.

The previous prime is 1265725777. The next prime is 1265725781. The reversal of 1265725779 is 9775275621.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1265725777) and next prime (1265725781).

It is a cyclic number.

It is not a de Polignac number, because 1265725779 - 2¹ = 1265725777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1265725777) 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, 210954294 + ... + 210954299.

It is an arithmetic number, because the mean of its divisors is an integer number (421908594).

Almost surely, 2^1265725779 is an apocalyptic number.

1265725779 is a deficient number, since it is larger than the sum of its proper divisors (421908597).

1265725779 is an equidigital number, since it uses as much as digits as its factorization.

1265725779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421908596.

The product of its digits is 1852200, while the sum is 51.

The square root of 1265725779 is about 35577.0400539449. The cubic root of 1265725779 is about 1081.7158877773.

The spelling of 1265725779 in words is "one billion, two hundred sixty-five million, seven hundred twenty-five thousand, seven hundred seventy-nine".