643244540066 has 32 divisors (see below), whose sum is σ = 987922960128. Its totient is φ = 314027677440.

The previous prime is 643244540033. The next prime is 643244540131. The reversal of 643244540066 is 660045442346.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 643244539999 and 643244540026.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58808150 + ... + 58819086.

It is an arithmetic number, because the mean of its divisors is an integer number (30872592504).

Almost surely, 2^643244540066 is an apocalyptic number.

643244540066 is a deficient number, since it is larger than the sum of its proper divisors (344678420062).

643244540066 is a wasteful number, since it uses less digits than its factorization.

643244540066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15026.

The product of its (nonzero) digits is 1658880, while the sum is 44.

The spelling of 643244540066 in words is "six hundred forty-three billion, two hundred forty-four million, five hundred forty thousand, sixty-six".