1606643920 has 80 divisors (see below), whose sum is σ = 4332901248. Its totient is φ = 542615040.

The previous prime is 1606643903. The next prime is 1606643923. The reversal of 1606643920 is 293466061.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 1606643920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1606643923) 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, 16110 + ... + 58930.

Almost surely, 2^1606643920 is an apocalyptic number.

1606643920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1606643920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2166450624).

1606643920 is an abundant number, since it is smaller than the sum of its proper divisors (2726257328).

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

1606643920 is a wasteful number, since it uses less digits than its factorization.

1606643920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42908 (or 42902 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 1606643920 is about 40082.9629643319. The cubic root of 1606643920 is about 1171.2237712846.

The spelling of 1606643920 in words is "one billion, six hundred six million, six hundred forty-three thousand, nine hundred twenty".