643264920 has 96 divisors (see below), whose sum is σ = 2181535200. Its totient is φ = 164077056.

The previous prime is 643264903. The next prime is 643264927. The reversal of 643264920 is 29462346.

643264920 is a `hidden beast` number, since 6 + 4 + 3 + 2 + 649 + 2 + 0 = 666.

643264920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643264927) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30565 + ... + 47124.

It is an arithmetic number, because the mean of its divisors is an integer number (22724325).

Almost surely, 2^643264920 is an apocalyptic number.

643264920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643264920 is an abundant number, since it is smaller than the sum of its proper divisors (1538270280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643264920 is a wasteful number, since it uses less digits than its factorization.

643264920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77729 (or 77722 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 643264920 is about 25362.6678407458. The cubic root of 643264920 is about 863.2368196431.

The spelling of 643264920 in words is "six hundred forty-three million, two hundred sixty-four thousand, nine hundred twenty".