643821160 has 32 divisors (see below), whose sum is σ = 1449384840. Its totient is φ = 257388544.

The previous prime is 643821151. The next prime is 643821169. The reversal of 643821160 is 61128346.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (643821151) and next prime (643821169).

It can be written as a sum of positive squares in 4 ways, for example, as 425431876 + 218389284 = 20626^2 + 14778^2 .

It is not an unprimeable number, because it can be changed into a prime (643821169) 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, 102264 + ... + 108376.

Almost surely, 2^643821160 is an apocalyptic number.

It is an amenable number.

643821160 is an abundant number, since it is smaller than the sum of its proper divisors (805563680).

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

643821160 is a wasteful number, since it uses less digits than its factorization.

643821160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8757 (or 8753 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 643821160 is about 25373.6311946083. The cubic root of 643821160 is about 863.4855655319.

The spelling of 643821160 in words is "six hundred forty-three million, eight hundred twenty-one thousand, one hundred sixty".