642897128 has 32 divisors (see below), whose sum is σ = 1235451360. Its totient is φ = 313467840.

The previous prime is 642897121. The next prime is 642897133. The reversal of 642897128 is 821798246.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (642897121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 300623 + ... + 302753.

It is an arithmetic number, because the mean of its divisors is an integer number (38607855).

Almost surely, 2^642897128 is an apocalyptic number.

It is an amenable number.

642897128 is a deficient number, since it is larger than the sum of its proper divisors (592554232).

642897128 is a wasteful number, since it uses less digits than its factorization.

642897128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3057 (or 3053 counting only the distinct ones).

The product of its digits is 387072, while the sum is 47.

The square root of 642897128 is about 25355.4161472455. The cubic root of 642897128 is about 863.0722673645.

It can be divided in two parts, 64289 and 7128, that added together give a palindrome (71417).

The spelling of 642897128 in words is "six hundred forty-two million, eight hundred ninety-seven thousand, one hundred twenty-eight".