1264805257 has 4 divisors (see below), whose sum is σ = 1265903380. Its totient is φ = 1263707136.

The previous prime is 1264805251. The next prime is 1264805261. The reversal of 1264805257 is 7525084621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7525084621 = 443 ⋅16986647.

It can be written as a sum of positive squares in 2 ways, for example, as 674752576 + 590052681 = 25976^2 + 24291^2 .

It is a cyclic number.

It is not a de Polignac number, because 1264805257 - 2¹¹ = 1264803209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1264805251) 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, 547332 + ... + 549637.

It is an arithmetic number, because the mean of its divisors is an integer number (316475845).

Almost surely, 2^1264805257 is an apocalyptic number.

It is an amenable number.

1264805257 is a deficient number, since it is larger than the sum of its proper divisors (1098123).

1264805257 is a wasteful number, since it uses less digits than its factorization.

1264805257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1098122.

The product of its (nonzero) digits is 134400, while the sum is 40.

The square root of 1264805257 is about 35564.1006775091. The cubic root of 1264805257 is about 1081.4535916893.

Adding to 1264805257 its reverse (7525084621), we get a palindrome (8789889878).

The spelling of 1264805257 in words is "one billion, two hundred sixty-four million, eight hundred five thousand, two hundred fifty-seven".