1643889213 has 6 divisors (see below), whose sum is σ = 2374506654. Its totient is φ = 1095926136.

The previous prime is 1643889209. The next prime is 1643889217. The reversal of 1643889213 is 3129883461.

It is an interprime number because it is at equal distance from previous prime (1643889209) and next prime (1643889217).

It can be written as a sum of positive squares in only one way, i.e., 1463980644 + 179908569 = 38262^2 + 13413^2 .

It is not a de Polignac number, because 1643889213 - 2² = 1643889209 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643889217) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 91327170 + ... + 91327187.

It is an arithmetic number, because the mean of its divisors is an integer number (395751109).

Almost surely, 2^1643889213 is an apocalyptic number.

It is an amenable number.

1643889213 is a deficient number, since it is larger than the sum of its proper divisors (730617441).

1643889213 is a wasteful number, since it uses less digits than its factorization.

1643889213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182654363 (or 182654360 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 1643889213 is about 40544.9036624827. The cubic root of 1643889213 is about 1180.2051766653.

The spelling of 1643889213 in words is "one billion, six hundred forty-three million, eight hundred eighty-nine thousand, two hundred thirteen".