641997128 has 16 divisors (see below), whose sum is σ = 1245253500. Its totient is φ = 309929536.

The previous prime is 641997127. The next prime is 641997133. The reversal of 641997128 is 821799146.

It can be written as a sum of positive squares in 2 ways, for example, as 641001124 + 996004 = 25318^2 + 998^2 .

It is not an unprimeable number, because it can be changed into a prime (641997127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1383383 + ... + 1383846.

Almost surely, 2^641997128 is an apocalyptic number.

It is an amenable number.

641997128 is a deficient number, since it is larger than the sum of its proper divisors (603256372).

641997128 is a wasteful number, since it uses less digits than its factorization.

641997128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2767264 (or 2767260 counting only the distinct ones).

The product of its digits is 217728, while the sum is 47.

The square root of 641997128 is about 25337.6622441771. The cubic root of 641997128 is about 862.6693372757.

The spelling of 641997128 in words is "six hundred forty-one million, nine hundred ninety-seven thousand, one hundred twenty-eight".