521440644 has 24 divisors (see below), whose sum is σ = 1219681120. Its totient is φ = 173386944.

The previous prime is 521440597. The next prime is 521440697. The reversal of 521440644 is 446044125.

It is a happy number.

It is a super-3 number, since 3×521440644³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48214 + ... + 58029.

Almost surely, 2^521440644 is an apocalyptic number.

It is an amenable number.

521440644 is an abundant number, since it is smaller than the sum of its proper divisors (698240476).

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

521440644 is a wasteful number, since it uses less digits than its factorization.

521440644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106659 (or 106657 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

The square root of 521440644 is about 22835.0748630260. The cubic root of 521440644 is about 804.8870867696.

Adding to 521440644 its reverse (446044125), we get a palindrome (967484769).

The spelling of 521440644 in words is "five hundred twenty-one million, four hundred forty thousand, six hundred forty-four".