1265551543 has 16 divisors (see below), whose sum is σ = 1313063136. Its totient is φ = 1219046400.

The previous prime is 1265551403. The next prime is 1265551549. The reversal of 1265551543 is 3451555621.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265551543 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 (1265551549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2105443 + ... + 2106043.

It is an arithmetic number, because the mean of its divisors is an integer number (82066446).

Almost surely, 2^1265551543 is an apocalyptic number.

1265551543 is a deficient number, since it is larger than the sum of its proper divisors (47511593).

1265551543 is an equidigital number, since it uses as much as digits as its factorization.

1265551543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314.

The product of its digits is 90000, while the sum is 37.

The square root of 1265551543 is about 35574.5912555577. The cubic root of 1265551543 is about 1081.6662502488. Note that the first 3 decimals are identical.

The spelling of 1265551543 in words is "one billion, two hundred sixty-five million, five hundred fifty-one thousand, five hundred forty-three".