1277478265 has 12 divisors (see below), whose sum is σ = 1783255716. Its totient is φ = 875984928.

The previous prime is 1277478247. The next prime is 1277478313. The reversal of 1277478265 is 5628747721.

It can be written as a sum of positive squares in 2 ways, for example, as 972940864 + 304537401 = 31192^2 + 17451^2 .

It is not a de Polignac number, because 1277478265 - 2¹⁵ = 1277445497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2606854 + ... + 2607343.

It is an arithmetic number, because the mean of its divisors is an integer number (148604643).

Almost surely, 2^1277478265 is an apocalyptic number.

It is an amenable number.

1277478265 is a deficient number, since it is larger than the sum of its proper divisors (505777451).

1277478265 is an equidigital number, since it uses as much as digits as its factorization.

1277478265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5214216 (or 5214209 counting only the distinct ones).

The product of its digits is 1317120, while the sum is 49.

The square root of 1277478265 is about 35741.8279470986. The cubic root of 1277478265 is about 1085.0535526811.

The spelling of 1277478265 in words is "one billion, two hundred seventy-seven million, four hundred seventy-eight thousand, two hundred sixty-five".