1261563257 has 8 divisors (see below), whose sum is σ = 1270441536. Its totient is φ = 1252701072.

The previous prime is 1261563223. The next prime is 1261563299. The reversal of 1261563257 is 7523651621.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261563257 - 2¹⁴ = 1261546873 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1261563257.

It is not an unprimeable number, because it can be changed into a prime (1261563157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 183158 + ... + 189920.

It is an arithmetic number, because the mean of its divisors is an integer number (158805192).

Almost surely, 2^1261563257 is an apocalyptic number.

It is an amenable number.

1261563257 is a deficient number, since it is larger than the sum of its proper divisors (8878279).

1261563257 is a wasteful number, since it uses less digits than its factorization.

1261563257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8047.

The product of its digits is 75600, while the sum is 38.

The square root of 1261563257 is about 35518.4917613347. The cubic root of 1261563257 is about 1080.5287925464.

The spelling of 1261563257 in words is "one billion, two hundred sixty-one million, five hundred sixty-three thousand, two hundred fifty-seven".