1265057657 has 4 divisors (see below), whose sum is σ = 1268395920. Its totient is φ = 1261719396.

The previous prime is 1265057653. The next prime is 1265057671. The reversal of 1265057657 is 7567505621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1265057657 - 2² = 1265057653 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1265057653) 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, 1668563 + ... + 1669320.

It is an arithmetic number, because the mean of its divisors is an integer number (317098980).

Almost surely, 2^1265057657 is an apocalyptic number.

It is an amenable number.

1265057657 is a deficient number, since it is larger than the sum of its proper divisors (3338263).

1265057657 is an equidigital number, since it uses as much as digits as its factorization.

1265057657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3338262.

The product of its (nonzero) digits is 441000, while the sum is 44.

The square root of 1265057657 is about 35567.6490226723. The cubic root of 1265057657 is about 1081.5255239045.

It can be divided in two parts, 12650 and 57657, that added together give a palindrome (70307).

The spelling of 1265057657 in words is "one billion, two hundred sixty-five million, fifty-seven thousand, six hundred fifty-seven".