1251801663 has 16 divisors (see below), whose sum is σ = 1919662080. Its totient is φ = 710757216.

The previous prime is 1251801641. The next prime is 1251801697. The reversal of 1251801663 is 3661081521.

It is not a de Polignac number, because 1251801663 - 2¹⁰ = 1251800639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251801163) 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 15 ways as a sum of consecutive naturals, for example, 186543 + ... + 193136.

It is an arithmetic number, because the mean of its divisors is an integer number (119978880).

Almost surely, 2^1251801663 is an apocalyptic number.

1251801663 is a deficient number, since it is larger than the sum of its proper divisors (667860417).

1251801663 is a wasteful number, since it uses less digits than its factorization.

1251801663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379846.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 1251801663 is about 35380.8092473872. The cubic root of 1251801663 is about 1077.7346386008.

The spelling of 1251801663 in words is "one billion, two hundred fifty-one million, eight hundred one thousand, six hundred sixty-three".