521261440 has 128 divisors (see below), whose sum is σ = 1432569600. Its totient is φ = 177666048.

The previous prime is 521261431. The next prime is 521261483. The reversal of 521261440 is 44162125.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

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, 1375171 + ... + 1375549.

It is an arithmetic number, because the mean of its divisors is an integer number (11191950).

Almost surely, 2^521261440 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 521261440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (716284800).

521261440 is an abundant number, since it is smaller than the sum of its proper divisors (911308160).

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

521261440 is a wasteful number, since it uses less digits than its factorization.

521261440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712 (or 700 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 521261440 is about 22831.1506499344. The cubic root of 521261440 is about 804.7948707690.

The spelling of 521261440 in words is "five hundred twenty-one million, two hundred sixty-one thousand, four hundred forty".