1643164240 has 40 divisors (see below), whose sum is σ = 4045087080. Its totient is φ = 618602496.

The previous prime is 1643164199. The next prime is 1643164241. The reversal of 1643164240 is 424613461.

It can be written as a sum of positive squares in 4 ways, for example, as 542517264 + 1100646976 = 23292^2 + 33176^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1643164240² = 5399977439229555200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643164241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 602745 + ... + 605464.

It is an arithmetic number, because the mean of its divisors is an integer number (101127177).

Almost surely, 2^1643164240 is an apocalyptic number.

1643164240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643164240 is an abundant number, since it is smaller than the sum of its proper divisors (2401922840).

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

1643164240 is a wasteful number, since it uses less digits than its factorization.

1643164240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1208239 (or 1208233 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 1643164240 is about 40535.9623050940. The cubic root of 1643164240 is about 1180.0316567204.

The spelling of 1643164240 in words is "one billion, six hundred forty-three million, one hundred sixty-four thousand, two hundred forty".