521998620 has 192 divisors, whose sum is σ = 1740178944. Its totient is φ = 115246080.

The previous prime is 521998619. The next prime is 521998621. The reversal of 521998620 is 26899125.

It is an interprime number because it is at equal distance from previous prime (521998619) and next prime (521998621).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521998621) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 711774 + ... + 712506.

It is an arithmetic number, because the mean of its divisors is an integer number (9063432).

Almost surely, 2^521998620 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 521998620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (870089472).

521998620 is an abundant number, since it is smaller than the sum of its proper divisors (1218180324).

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

521998620 is a wasteful number, since it uses less digits than its factorization.

521998620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 852 (or 850 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 521998620 is about 22847.2891170922. The cubic root of 521998620 is about 805.1740785783.

The spelling of 521998620 in words is "five hundred twenty-one million, nine hundred ninety-eight thousand, six hundred twenty".