521253720 has 192 divisors, whose sum is σ = 1840849920. Its totient is φ = 127153152.

The previous prime is 521253713. The next prime is 521253749. The reversal of 521253720 is 27352125.

It is a super-2 number, since 2×521253720² = 543410881227676800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 593922 + ... + 594798.

It is an arithmetic number, because the mean of its divisors is an integer number (9587760).

Almost surely, 2^521253720 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 521253720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (920424960).

521253720 is an abundant number, since it is smaller than the sum of its proper divisors (1319596200).

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

521253720 is a wasteful number, since it uses less digits than its factorization.

521253720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1034 (or 1027 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 521253720 is about 22830.9815820521. The cubic root of 521253720 is about 804.7908976846.

The spelling of 521253720 in words is "five hundred twenty-one million, two hundred fifty-three thousand, seven hundred twenty".