1263553261 has 4 divisors (see below), whose sum is σ = 1264263712. Its totient is φ = 1262842812.

The previous prime is 1263553243. The next prime is 1263553279. The reversal of 1263553261 is 1623553621.

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 an interprime number because it is at equal distance from previous prime (1263553243) and next prime (1263553279).

It is a cyclic number.

It is not a de Polignac number, because 1263553261 - 2¹¹ = 1263551213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1263553061) 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, 352551 + ... + 356116.

It is an arithmetic number, because the mean of its divisors is an integer number (316065928).

Almost surely, 2^1263553261 is an apocalyptic number.

It is an amenable number.

1263553261 is a deficient number, since it is larger than the sum of its proper divisors (710451).

1263553261 is an equidigital number, since it uses as much as digits as its factorization.

1263553261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 710450.

The product of its digits is 32400, while the sum is 34.

The square root of 1263553261 is about 35546.4943559840. The cubic root of 1263553261 is about 1081.0966401445.

The spelling of 1263553261 in words is "one billion, two hundred sixty-three million, five hundred fifty-three thousand, two hundred sixty-one".