521390840 has 32 divisors (see below), whose sum is σ = 1173782880. Its totient is φ = 208440192.

The previous prime is 521390813. The next prime is 521390861. The reversal of 521390840 is 48093125.

It is a junction number, because it is equal to n+sod(n) for n = 521390797 and 521390806.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 128117 + ... + 132123.

It is an arithmetic number, because the mean of its divisors is an integer number (36680715).

Almost surely, 2^521390840 is an apocalyptic number.

It is an amenable number.

521390840 is an abundant number, since it is smaller than the sum of its proper divisors (652392040).

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

521390840 is a wasteful number, since it uses less digits than its factorization.

521390840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7271 (or 7267 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 521390840 is about 22833.9843216203. The cubic root of 521390840 is about 804.8614604123.

The spelling of 521390840 in words is "five hundred twenty-one million, three hundred ninety thousand, eight hundred forty".