1251663 has 16 divisors (see below), whose sum is σ = 2008320. Its totient is φ = 677376.

The previous prime is 1251661. The next prime is 1251667. The reversal of 1251663 is 3661521.

It is not a de Polignac number, because 1251663 - 2¹ = 1251661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1170 + ... + 1967.

It is an arithmetic number, because the mean of its divisors is an integer number (125520).

2^1251663 is an apocalyptic number.

1251663 is a deficient number, since it is larger than the sum of its proper divisors (756657).

1251663 is a wasteful number, since it uses less digits than its factorization.

1251663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3166.

The product of its digits is 1080, while the sum is 24.

The square root of 1251663 is about 1118.7774577636. Note that the first 3 decimals coincide. The cubic root of 1251663 is about 107.7694843309.

The spelling of 1251663 in words is "one million, two hundred fifty-one thousand, six hundred sixty-three".