1251351649 has 4 divisors (see below), whose sum is σ = 1252607764. Its totient is φ = 1250095536.

The previous prime is 1251351631. The next prime is 1251351667. The reversal of 1251351649 is 9461531521.

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

It is an interprime number because it is at equal distance from previous prime (1251351631) and next prime (1251351667).

It can be written as a sum of positive squares in 2 ways, for example, as 582353424 + 668998225 = 24132^2 + 25865^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251351649 - 2¹⁷ = 1251220577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1251351679) by changing a digit.

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, 626562 + ... + 628555.

It is an arithmetic number, because the mean of its divisors is an integer number (313151941).

Almost surely, 2^1251351649 is an apocalyptic number.

It is an amenable number.

1251351649 is a deficient number, since it is larger than the sum of its proper divisors (1256115).

1251351649 is an equidigital number, since it uses as much as digits as its factorization.

1251351649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1256114.

The product of its digits is 32400, while the sum is 37.

The square root of 1251351649 is about 35374.4490981838. The cubic root of 1251351649 is about 1077.6054770839.

The spelling of 1251351649 in words is "one billion, two hundred fifty-one million, three hundred fifty-one thousand, six hundred forty-nine".