1643689120 has 24 divisors (see below), whose sum is σ = 3883215924. Its totient is φ = 657475584.

The previous prime is 1643689111. The next prime is 1643689129. The reversal of 1643689120 is 219863461.

It is an interprime number because it is at equal distance from previous prime (1643689111) and next prime (1643689129).

It can be written as a sum of positive squares in 2 ways, for example, as 1634423184 + 9265936 = 40428^2 + 3044^2 .

It is a super-3 number, since 3×1643689120³ (a number of 29 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (1643689129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5136369 + ... + 5136688.

Almost surely, 2^1643689120 is an apocalyptic number.

1643689120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643689120 is an abundant number, since it is smaller than the sum of its proper divisors (2239526804).

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

1643689120 is a wasteful number, since it uses less digits than its factorization.

1643689120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10273072 (or 10273064 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 1643689120 is about 40542.4360392910. The cubic root of 1643689120 is about 1180.1572901503.

The spelling of 1643689120 in words is "one billion, six hundred forty-three million, six hundred eighty-nine thousand, one hundred twenty".