1255665521 has 12 divisors (see below), whose sum is σ = 1452838800. Its totient is φ = 1081432440.

The previous prime is 1255665511. The next prime is 1255665563.

1255665521 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1255665521 - 2¹⁰ = 1255664497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1255665511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 270791 + ... + 275388.

It is an arithmetic number, because the mean of its divisors is an integer number (121069900).

Almost surely, 2^1255665521 is an apocalyptic number.

1255665521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1255665521 is a deficient number, since it is larger than the sum of its proper divisors (197173279).

1255665521 is a wasteful number, since it uses less digits than its factorization.

1255665521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546220 (or 546209 counting only the distinct ones).

The product of its digits is 90000, while the sum is 38.

The square root of 1255665521 is about 35435.3710436338. The cubic root of 1255665521 is about 1078.8423584011.

The spelling of 1255665521 in words is "one billion, two hundred fifty-five million, six hundred sixty-five thousand, five hundred twenty-one".