1256021713 has 4 divisors (see below), whose sum is σ = 1256402340. Its totient is φ = 1255641088.

The previous prime is 1256021687. The next prime is 1256021729. The reversal of 1256021713 is 3171206521.

It is a happy number.

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 769951504 + 486070209 = 27748^2 + 22047^2 .

It is a cyclic number.

It is not a de Polignac number, because 1256021713 - 2²⁹ = 719150801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256021783) 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, 185320 + ... + 191977.

It is an arithmetic number, because the mean of its divisors is an integer number (314100585).

Almost surely, 2^1256021713 is an apocalyptic number.

It is an amenable number.

1256021713 is a deficient number, since it is larger than the sum of its proper divisors (380627).

1256021713 is an equidigital number, since it uses as much as digits as its factorization.

1256021713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380626.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 1256021713 is about 35440.3966258844. The cubic root of 1256021713 is about 1078.9443597385.

The spelling of 1256021713 in words is "one billion, two hundred fifty-six million, twenty-one thousand, seven hundred thirteen".