521213840 has 80 divisors (see below), whose sum is σ = 1404552960. Its totient is φ = 176171520.

The previous prime is 521213827. The next prime is 521213843. The reversal of 521213840 is 48312125.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (521213843) 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 in 15 ways as a sum of consecutive naturals, for example, 33206 + ... + 46314.

It is an arithmetic number, because the mean of its divisors is an integer number (17556912).

Almost surely, 2^521213840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521213840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (702276480).

521213840 is an abundant number, since it is smaller than the sum of its proper divisors (883339120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521213840 is a wasteful number, since it uses less digits than its factorization.

521213840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13200 (or 13194 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 521213840 is about 22830.1081907204. The cubic root of 521213840 is about 804.7703728881.

Adding to 521213840 its reverse (48312125), we get a palindrome (569525965).

The spelling of 521213840 in words is "five hundred twenty-one million, two hundred thirteen thousand, eight hundred forty".