521400720 has 80 divisors (see below), whose sum is σ = 1626145920. Its totient is φ = 138196992.

The previous prime is 521400709. The next prime is 521400743. The reversal of 521400720 is 27004125.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33576 + ... + 46584.

It is an arithmetic number, because the mean of its divisors is an integer number (20326824).

Almost surely, 2^521400720 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 521400720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (813072960).

521400720 is an abundant number, since it is smaller than the sum of its proper divisors (1104745200).

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

521400720 is a wasteful number, since it uses less digits than its factorization.

521400720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13192 (or 13186 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 521400720 is about 22834.2006647923. The cubic root of 521400720 is about 804.8665442383.

Adding to 521400720 its reverse (27004125), we get a palindrome (548404845).

The spelling of 521400720 in words is "five hundred twenty-one million, four hundred thousand, seven hundred twenty".