521421999120 has 360 divisors, whose sum is σ = 1926928215576. Its totient is φ = 126263808000.

The previous prime is 521421999113. The next prime is 521421999121. The reversal of 521421999120 is 21999124125.

521421999120 is a `hidden beast` number, since 52 + 1 + 421 + 99 + 91 + 2 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 238019088384 + 283402910736 = 487872^2 + 532356^2 .

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (521421999121) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 92431500 + ... + 92437140.

Almost surely, 2^521421999120 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 521421999120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (963464107788).

521421999120 is an abundant number, since it is smaller than the sum of its proper divisors (1405506216456).

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

521421999120 is a wasteful number, since it uses less digits than its factorization.

521421999120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6743 (or 6723 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The spelling of 521421999120 in words is "five hundred twenty-one billion, four hundred twenty-one million, nine hundred ninety-nine thousand, one hundred twenty".