1251273663 has 20 divisors (see below), whose sum is σ = 1899836488. Its totient is φ = 820504080.

The previous prime is 1251273601. The next prime is 1251273689. The reversal of 1251273663 is 3663721521.

1251273663 is a `hidden beast` number, since 12 + 512 + 73 + 6 + 63 = 666.

It is not a de Polignac number, because 1251273663 - 2⁸ = 1251273407 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 (1251272663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 121681 + ... + 131562.

Almost surely, 2^1251273663 is an apocalyptic number.

1251273663 is a deficient number, since it is larger than the sum of its proper divisors (648562825).

1251273663 is an equidigital number, since it uses as much as digits as its factorization.

1251273663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253316 (or 253307 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 1251273663 is about 35373.3467882246. The cubic root of 1251273663 is about 1077.5830906544.

The spelling of 1251273663 in words is "one billion, two hundred fifty-one million, two hundred seventy-three thousand, six hundred sixty-three".