521397240 has 384 divisors, whose sum is σ = 2068416000. Its totient is φ = 103928832.

The previous prime is 521397211. The next prime is 521397251. The reversal of 521397240 is 42793125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1452181 + ... + 1452539.

It is an arithmetic number, because the mean of its divisors is an integer number (5386500).

Almost surely, 2^521397240 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 521397240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1034208000).

521397240 is an abundant number, since it is smaller than the sum of its proper divisors (1547018760).

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

521397240 is a wasteful number, since it uses less digits than its factorization.

521397240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419 (or 408 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 521397240 is about 22834.1244631801. The cubic root of 521397240 is about 804.8647535863.

The spelling of 521397240 in words is "five hundred twenty-one million, three hundred ninety-seven thousand, two hundred forty".