1265156005 has 4 divisors (see below), whose sum is σ = 1518187212. Its totient is φ = 1012124800.

The previous prime is 1265155999. The next prime is 1265156041. The reversal of 1265156005 is 5006515621.

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 719419684 + 545736321 = 26822^2 + 23361^2 .

It is not a de Polignac number, because 1265156005 - 2¹⁷ = 1265024933 is a prime.

It is a Duffinian number.

It is a congruent 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, 126515596 + ... + 126515605.

It is an arithmetic number, because the mean of its divisors is an integer number (379546803).

Almost surely, 2^1265156005 is an apocalyptic number.

It is an amenable number.

1265156005 is a deficient number, since it is larger than the sum of its proper divisors (253031207).

1265156005 is an equidigital number, since it uses as much as digits as its factorization.

1265156005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253031206.

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 1265156005 is about 35569.0315443083. The cubic root of 1265156005 is about 1081.5535497987.

The spelling of 1265156005 in words is "one billion, two hundred sixty-five million, one hundred fifty-six thousand, five".