643563670 has 16 divisors (see below), whose sum is σ = 1162725840. Its totient is φ = 256467424.

The previous prime is 643563643. The next prime is 643563677. The reversal of 643563670 is 76365346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643563677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116932 + ... + 122311.

It is an arithmetic number, because the mean of its divisors is an integer number (72670365).

Almost surely, 2^643563670 is an apocalyptic number.

643563670 is a deficient number, since it is larger than the sum of its proper divisors (519162170).

643563670 is a wasteful number, since it uses less digits than its factorization.

643563670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239519.

The product of its (nonzero) digits is 272160, while the sum is 40.

The square root of 643563670 is about 25368.5567188991. The cubic root of 643563670 is about 863.3704359693.

The spelling of 643563670 in words is "six hundred forty-three million, five hundred sixty-three thousand, six hundred seventy".