521620561 has 16 divisors (see below), whose sum is σ = 667912320. Its totient is φ = 395470080.

The previous prime is 521620493. The next prime is 521620579. The reversal of 521620561 is 165026125.

It is a cyclic number.

It is not a de Polignac number, because 521620561 - 2¹³ = 521612369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521624561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88696 + ... + 94393.

It is an arithmetic number, because the mean of its divisors is an integer number (41744520).

Almost surely, 2^521620561 is an apocalyptic number.

It is an amenable number.

521620561 is a deficient number, since it is larger than the sum of its proper divisors (146291759).

521620561 is a wasteful number, since it uses less digits than its factorization.

521620561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183144.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 521620561 is about 22839.0140111170. The cubic root of 521620561 is about 804.9796484188.

Adding to 521620561 its reverse (165026125), we get a palindrome (686646686).

The spelling of 521620561 in words is "five hundred twenty-one million, six hundred twenty thousand, five hundred sixty-one".