1646993663 has 16 divisors (see below), whose sum is σ = 1984323840. Its totient is φ = 1335398400.

The previous prime is 1646993641. The next prime is 1646993669. The reversal of 1646993663 is 3663996461.

It is not a de Polignac number, because 1646993663 - 2²⁰ = 1645945087 is a prime.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1646993669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82943 + ... + 100863.

It is an arithmetic number, because the mean of its divisors is an integer number (124020240).

Almost surely, 2^1646993663 is an apocalyptic number.

1646993663 is a deficient number, since it is larger than the sum of its proper divisors (337330177).

1646993663 is a wasteful number, since it uses less digits than its factorization.

1646993663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18638.

The product of its digits is 3779136, while the sum is 53.

The square root of 1646993663 is about 40583.1697012444. The cubic root of 1646993663 is about 1180.9476403214.

The spelling of 1646993663 in words is "one billion, six hundred forty-six million, nine hundred ninety-three thousand, six hundred sixty-three".