643740706 has 16 divisors (see below), whose sum is σ = 1106199360. Its totient is φ = 275227920.

The previous prime is 643740701. The next prime is 643740707. The reversal of 643740706 is 607047346.

It is a super-2 number, since 2×643740706² = 828804193122756872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643740701) 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, 49005 + ... + 60736.

It is an arithmetic number, because the mean of its divisors is an integer number (69137460).

Almost surely, 2^643740706 is an apocalyptic number.

643740706 is a deficient number, since it is larger than the sum of its proper divisors (462458654).

643740706 is a wasteful number, since it uses less digits than its factorization.

643740706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110169.

The product of its (nonzero) digits is 84672, while the sum is 37.

The square root of 643740706 is about 25372.0457590633. The cubic root of 643740706 is about 863.4495960392.

It can be divided in two parts, 643740 and 706, that added together give a palindrome (644446).

The spelling of 643740706 in words is "six hundred forty-three million, seven hundred forty thousand, seven hundred six".