1280421663 has 4 divisors (see below), whose sum is σ = 1707228888. Its totient is φ = 853614440.

The previous prime is 1280421643. The next prime is 1280421689. The reversal of 1280421663 is 3661240821.

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

It is a cyclic number.

It is not a de Polignac number, because 1280421663 - 2¹⁶ = 1280356127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1280421643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213403608 + ... + 213403613.

It is an arithmetic number, because the mean of its divisors is an integer number (426807222).

Almost surely, 2^1280421663 is an apocalyptic number.

1280421663 is a deficient number, since it is larger than the sum of its proper divisors (426807225).

1280421663 is an equidigital number, since it uses as much as digits as its factorization.

1280421663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426807224.

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 1280421663 is about 35782.9800743314. The cubic root of 1280421663 is about 1085.8862595354.

The spelling of 1280421663 in words is "one billion, two hundred eighty million, four hundred twenty-one thousand, six hundred sixty-three".