643221642 has 16 divisors (see below), whose sum is σ = 1470220992. Its totient is φ = 183777600.

The previous prime is 643221617. The next prime is 643221661. The reversal of 643221642 is 246122346.

It is an unprimeable number.

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, 7657359 + ... + 7657442.

It is an arithmetic number, because the mean of its divisors is an integer number (91888812).

Almost surely, 2^643221642 is an apocalyptic number.

643221642 is an abundant number, since it is smaller than the sum of its proper divisors (826999350).

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

643221642 is a wasteful number, since it uses less digits than its factorization.

643221642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15314813.

The product of its digits is 13824, while the sum is 30.

The square root of 643221642 is about 25361.8146432782. The cubic root of 643221642 is about 863.2174600710.

Adding to 643221642 its reverse (246122346), we get a palindrome (889343988).

The spelling of 643221642 in words is "six hundred forty-three million, two hundred twenty-one thousand, six hundred forty-two".