521998 has 4 divisors (see below), whose sum is σ = 783000. Its totient is φ = 260998.

The previous prime is 521993. The next prime is 521999. The reversal of 521998 is 899125.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521993) 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 as a sum of consecutive naturals, namely, 130498 + ... + 130501.

It is an arithmetic number, because the mean of its divisors is an integer number (195750).

2⁵²¹⁹⁹⁸ is an apocalyptic number.

521998 is a deficient number, since it is larger than the sum of its proper divisors (261002).

521998 is a wasteful number, since it uses less digits than its factorization.

521998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261001.

The product of its digits is 6480, while the sum is 34.

The square root of 521998 is about 722.4942906349. The cubic root of 521998 is about 80.5173759798.

The spelling of 521998 in words is "five hundred twenty-one thousand, nine hundred ninety-eight".