1251056005 has 4 divisors (see below), whose sum is σ = 1501267212. Its totient is φ = 1000844800.

The previous prime is 1251055999. The next prime is 1251056039. The reversal of 1251056005 is 5006501521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5006501521 = 7 ⋅715214503.

It can be written as a sum of positive squares in 2 ways, for example, as 734084836 + 516971169 = 27094^2 + 22737^2 .

It is not a de Polignac number, because 1251056005 - 2⁹ = 1251055493 is a prime.

It is a super-2 number, since 2×1251056005² = 3130282255293120050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 125105596 + ... + 125105605.

It is an arithmetic number, because the mean of its divisors is an integer number (375316803).

Almost surely, 2^1251056005 is an apocalyptic number.

It is an amenable number.

1251056005 is a deficient number, since it is larger than the sum of its proper divisors (250211207).

1251056005 is an equidigital number, since it uses as much as digits as its factorization.

1251056005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250211206.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 1251056005 is about 35370.2700724775. The cubic root of 1251056005 is about 1077.5206054741.

Adding to 1251056005 its reverse (5006501521), we get a palindrome (6257557526).

The spelling of 1251056005 in words is "one billion, two hundred fifty-one million, fifty-six thousand, five".