1643221803 has 8 divisors (see below), whose sum is σ = 2228097600. Its totient is φ = 1076913608.

The previous prime is 1643221793. The next prime is 1643221813. The reversal of 1643221803 is 3081223461.

1643221803 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (1643221793) and next prime (1643221813).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1643221803 - 2⁴ = 1643221787 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1643221813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4641693 + ... + 4642046.

It is an arithmetic number, because the mean of its divisors is an integer number (278512200).

Almost surely, 2^1643221803 is an apocalyptic number.

1643221803 is a deficient number, since it is larger than the sum of its proper divisors (584875797).

1643221803 is an equidigital number, since it uses as much as digits as its factorization.

1643221803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9283801.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 1643221803 is about 40536.6723227253. The cubic root of 1643221803 is about 1180.0454361036.

It can be divided in two parts, 1643 and 221803, that added together give a triangular number (223446 = T₆₆₈).

The spelling of 1643221803 in words is "one billion, six hundred forty-three million, two hundred twenty-one thousand, eight hundred three".