643928157 has 8 divisors (see below), whose sum is σ = 953967680. Its totient is φ = 429285420.

The previous prime is 643928147. The next prime is 643928167. The reversal of 643928157 is 751829346.

It is an interprime number because it is at equal distance from previous prime (643928147) and next prime (643928167).

It is not a de Polignac number, because 643928157 - 2⁷ = 643928029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643928147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11924569 + ... + 11924622.

It is an arithmetic number, because the mean of its divisors is an integer number (119245960).

Almost surely, 2^643928157 is an apocalyptic number.

It is an amenable number.

643928157 is a deficient number, since it is larger than the sum of its proper divisors (310039523).

643928157 is a wasteful number, since it uses less digits than its factorization.

643928157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23849200 (or 23849194 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 643928157 is about 25375.7395360214. The cubic root of 643928157 is about 863.5333972659.

It can be divided in two parts, 6439 and 28157, that added together give a square (34596 = 186²).

The spelling of 643928157 in words is "six hundred forty-three million, nine hundred twenty-eight thousand, one hundred fifty-seven".