1277561265 has 16 divisors (see below), whose sum is σ = 2045013696. Its totient is φ = 681060800.

The previous prime is 1277561251. The next prime is 1277561267. The reversal of 1277561265 is 5621657721.

It is a happy number.

It is not a de Polignac number, because 1277561265 - 2⁴ = 1277561249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1277561267) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17830 + ... + 53600.

It is an arithmetic number, because the mean of its divisors is an integer number (127813356).

Almost surely, 2^1277561265 is an apocalyptic number.

1277561265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1277561265 is a deficient number, since it is larger than the sum of its proper divisors (767452431).

1277561265 is a wasteful number, since it uses less digits than its factorization.

1277561265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38160.

The product of its digits is 176400, while the sum is 42.

The square root of 1277561265 is about 35742.9890328159. The cubic root of 1277561265 is about 1085.0770514486.

The spelling of 1277561265 in words is "one billion, two hundred seventy-seven million, five hundred sixty-one thousand, two hundred sixty-five".