1643223645 has 128 divisors (see below), whose sum is σ = 3566592000. Its totient is φ = 701084160.

The previous prime is 1643223599. The next prime is 1643223653. The reversal of 1643223645 is 5463223461.

1643223645 is a `hidden beast` number, since 1 + 6 + 4 + 3 + 2 + 2 + 3 + 645 = 666.

It is not a de Polignac number, because 1643223645 - 2¹¹ = 1643221597 is a prime.

It is a congruent number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 1274161 + ... + 1275449.

It is an arithmetic number, because the mean of its divisors is an integer number (27864000).

Almost surely, 2^1643223645 is an apocalyptic number.

1643223645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1643223645 is an abundant number, since it is smaller than the sum of its proper divisors (1923368355).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1643223645 is a wasteful number, since it uses less digits than its factorization.

1643223645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400 (or 1394 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 1643223645 is about 40536.6950428868. The cubic root of 1643223645 is about 1180.0458770347.

The spelling of 1643223645 in words is "one billion, six hundred forty-three million, two hundred twenty-three thousand, six hundred forty-five".