521355420 has 96 divisors (see below), whose sum is σ = 1628605440. Its totient is φ = 138461760.

The previous prime is 521355413. The next prime is 521355433. The reversal of 521355420 is 24553125.

It is a happy number.

It is a super-2 number, since 2×521355420² = 543622947926752800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 in 31 ways as a sum of consecutive naturals, for example, 140185 + ... + 143855.

It is an arithmetic number, because the mean of its divisors is an integer number (16964640).

Almost surely, 2^521355420 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 521355420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (814302720).

521355420 is an abundant number, since it is smaller than the sum of its proper divisors (1107250020).

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

521355420 is a wasteful number, since it uses less digits than its factorization.

521355420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3952 (or 3944 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 27.

The square root of 521355420 is about 22833.2087101222. The cubic root of 521355420 is about 804.8432342652.

The spelling of 521355420 in words is "five hundred twenty-one million, three hundred fifty-five thousand, four hundred twenty".