642898 has 4 divisors (see below), whose sum is σ = 964350. Its totient is φ = 321448.

The previous prime is 642881. The next prime is 642899. The reversal of 642898 is 898246.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 597529 + 45369 = 773^2 + 213^2 .

It is not an unprimeable number, because it can be changed into a prime (642899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160723 + ... + 160726.

2⁶⁴²⁸⁹⁸ is an apocalyptic number.

642898 is a deficient number, since it is larger than the sum of its proper divisors (321452).

642898 is a wasteful number, since it uses less digits than its factorization.

642898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321451.

The product of its digits is 27648, while the sum is 37.

The square root of 642898 is about 801.8092042375. The cubic root of 642898 is about 86.3072657577.

It can be divided in two parts, 642 and 898, that added together give a triangular number (1540 = T₅₅).

The spelling of 642898 in words is "six hundred forty-two thousand, eight hundred ninety-eight".