521259990 has 64 divisors (see below), whose sum is σ = 1281733632. Its totient is φ = 135632000.

The previous prime is 521259989. The next prime is 521260013. The reversal of 521259990 is 99952125.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 213919 + ... + 216341.

It is an arithmetic number, because the mean of its divisors is an integer number (20027088).

Almost surely, 2^521259990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 521259990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (640866816).

521259990 is an abundant number, since it is smaller than the sum of its proper divisors (760473642).

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

521259990 is a wasteful number, since it uses less digits than its factorization.

521259990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2605.

The product of its (nonzero) digits is 72900, while the sum is 42.

The square root of 521259990 is about 22831.1188950520. The cubic root of 521259990 is about 804.7941245321.

The spelling of 521259990 in words is "five hundred twenty-one million, two hundred fifty-nine thousand, nine hundred ninety".