1643683960 has 32 divisors (see below), whose sum is σ = 3859086240. Its totient is φ = 628887424.

The previous prime is 1643683919. The next prime is 1643683961. The reversal of 1643683960 is 693863461.

It is a super-2 number, since 2×1643683960² = 5403393920722563200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a self number, because there is not a number n which added to its sum of digits gives 1643683960.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643683961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 892387 + ... + 894226.

It is an arithmetic number, because the mean of its divisors is an integer number (120596445).

Almost surely, 2^1643683960 is an apocalyptic number.

1643683960 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643683960 is an abundant number, since it is smaller than the sum of its proper divisors (2215402280).

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

1643683960 is a wasteful number, since it uses less digits than its factorization.

1643683960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1786647 (or 1786643 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 46.

The square root of 1643683960 is about 40542.3724022164. The cubic root of 1643683960 is about 1180.1560552010.

The spelling of 1643683960 in words is "one billion, six hundred forty-three million, six hundred eighty-three thousand, nine hundred sixty".