1256122001 has 4 divisors (see below), whose sum is σ = 1264552500. Its totient is φ = 1247691504.

The previous prime is 1256121983. The next prime is 1256122003. The reversal of 1256122001 is 1002216521.

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 388878400 + 867243601 = 19720^2 + 29449^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256122001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256122003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4215026 + ... + 4215323.

It is an arithmetic number, because the mean of its divisors is an integer number (316138125).

Almost surely, 2^1256122001 is an apocalyptic number.

It is an amenable number.

1256122001 is a deficient number, since it is larger than the sum of its proper divisors (8430499).

1256122001 is an equidigital number, since it uses as much as digits as its factorization.

1256122001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8430498.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 1256122001 is about 35441.8114802277. The cubic root of 1256122001 is about 1078.9730753493.

Adding to 1256122001 its reverse (1002216521), we get a palindrome (2258338522).

The spelling of 1256122001 in words is "one billion, two hundred fifty-six million, one hundred twenty-two thousand, one".