1643662646 has 24 divisors (see below), whose sum is σ = 2623892160. Its totient is φ = 772060032.

The previous prime is 1643662577. The next prime is 1643662661. The reversal of 1643662646 is 6462663461.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1643662597 and 1643662606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 351995 + ... + 356633.

It is an arithmetic number, because the mean of its divisors is an integer number (109328840).

Almost surely, 2^1643662646 is an apocalyptic number.

1643662646 is a deficient number, since it is larger than the sum of its proper divisors (980229514).

1643662646 is a wasteful number, since it uses less digits than its factorization.

1643662646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5288 (or 5271 counting only the distinct ones).

The product of its digits is 746496, while the sum is 44.

The square root of 1643662646 is about 40542.1095405752. The cubic root of 1643662646 is about 1180.1509540673.

The spelling of 1643662646 in words is "one billion, six hundred forty-three million, six hundred sixty-two thousand, six hundred forty-six".