643192956 has 72 divisors (see below), whose sum is σ = 1870529024. Its totient is φ = 182541600.

The previous prime is 643192951. The next prime is 643192961. The reversal of 643192956 is 659291346.

643192956 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643192951) and next prime (643192961).

It is a super-3 number, since 3×643192956³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643192951) 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, 29601 + ... + 46503.

Almost surely, 2^643192956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643192956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (935264512).

643192956 is an abundant number, since it is smaller than the sum of its proper divisors (1227336068).

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

643192956 is a wasteful number, since it uses less digits than its factorization.

643192956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17071 (or 17066 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 643192956 is about 25361.2491017300. The cubic root of 643192956 is about 863.2046274678.

The spelling of 643192956 in words is "six hundred forty-three million, one hundred ninety-two thousand, nine hundred fifty-six".