643654755 has 48 divisors (see below), whose sum is σ = 1168038144. Its totient is φ = 340005600.

The previous prime is 643654741. The next prime is 643654757. The reversal of 643654755 is 557456346.

643654755 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 643654755 - 2⁵ = 643654723 is a prime.

It is a super-2 number, since 2×643654755² = 828582887268220050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 643654755.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643654757) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 127530 + ... + 132480.

It is an arithmetic number, because the mean of its divisors is an integer number (24334128).

Almost surely, 2^643654755 is an apocalyptic number.

643654755 is a deficient number, since it is larger than the sum of its proper divisors (524383389).

643654755 is a wasteful number, since it uses less digits than its factorization.

643654755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5078 (or 5066 counting only the distinct ones).

The product of its digits is 1512000, while the sum is 45.

The square root of 643654755 is about 25370.3518895580. The cubic root of 643654755 is about 863.4111656283.

The spelling of 643654755 in words is "six hundred forty-three million, six hundred fifty-four thousand, seven hundred fifty-five".