521842 has 4 divisors (see below), whose sum is σ = 782766. Its totient is φ = 260920.

The previous prime is 521831. The next prime is 521861. The reversal of 521842 is 248125.

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., 463761 + 58081 = 681^2 + 241^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a d-powerful number, because it can be written as 5⁸ + 2⁶ + 8² + 1 + 4² + 2¹⁷ .

It is an unprimeable number.

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, 130459 + ... + 130462.

2⁵²¹⁸⁴² is an apocalyptic number.

521842 is a deficient number, since it is larger than the sum of its proper divisors (260924).

521842 is a wasteful number, since it uses less digits than its factorization.

521842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260923.

The product of its digits is 640, while the sum is 22.

The square root of 521842 is about 722.3863232371. The cubic root of 521842 is about 80.5093542619.

Adding to 521842 its reverse (248125), we get a palindrome (769967).

The spelling of 521842 in words is "five hundred twenty-one thousand, eight hundred forty-two".