1256534221 has 4 divisors (see below), whose sum is σ = 1262021500. Its totient is φ = 1251046944.

The previous prime is 1256534161. The next prime is 1256534249. The reversal of 1256534221 is 1224356521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1217032996 + 39501225 = 34886^2 + 6285^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256534221 - 2⁹ = 1256533709 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 (1256534021) 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, 2743296 + ... + 2743753.

It is an arithmetic number, because the mean of its divisors is an integer number (315505375).

Almost surely, 2^1256534221 is an apocalyptic number.

It is an amenable number.

1256534221 is a deficient number, since it is larger than the sum of its proper divisors (5487279).

1256534221 is an equidigital number, since it uses as much as digits as its factorization.

1256534221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5487278.

The product of its digits is 14400, while the sum is 31.

The square root of 1256534221 is about 35447.6264508641. The cubic root of 1256534221 is about 1079.0910908595.

The spelling of 1256534221 in words is "one billion, two hundred fifty-six million, five hundred thirty-four thousand, two hundred twenty-one".