643220554 has 16 divisors (see below), whose sum is σ = 980733600. Its totient is φ = 316352304.

The previous prime is 643220497. The next prime is 643220573. The reversal of 643220554 is 455022346.

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, 19689 + ... + 40915.

It is an arithmetic number, because the mean of its divisors is an integer number (61295850).

Almost surely, 2^643220554 is an apocalyptic number.

643220554 is a deficient number, since it is larger than the sum of its proper divisors (337513046).

643220554 is a wasteful number, since it uses less digits than its factorization.

643220554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21477.

The product of its (nonzero) digits is 28800, while the sum is 31.

The square root of 643220554 is about 25361.7931936998. The cubic root of 643220554 is about 863.2169733641.

The spelling of 643220554 in words is "six hundred forty-three million, two hundred twenty thousand, five hundred fifty-four".