1256116521 has 8 divisors (see below), whose sum is σ = 1827078624. Its totient is φ = 761282720.

The previous prime is 1256116513. The next prime is 1256116523.

1256116521 is nontrivially palindromic in base 10.

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

It is not a de Polignac number, because 1256116521 - 2³ = 1256116513 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1256116523) 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, 19032036 + ... + 19032101.

It is an arithmetic number, because the mean of its divisors is an integer number (228384828).

Almost surely, 2^1256116521 is an apocalyptic number.

1256116521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1256116521 is a deficient number, since it is larger than the sum of its proper divisors (570962103).

1256116521 is a wasteful number, since it uses less digits than its factorization.

1256116521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38064151.

The product of its digits is 3600, while the sum is 30.

The square root of 1256116521 is about 35441.7341703252. The cubic root of 1256116521 is about 1078.9715062923.

The spelling of 1256116521 in words is "one billion, two hundred fifty-six million, one hundred sixteen thousand, five hundred twenty-one".