521320261 has 48 divisors (see below), whose sum is σ = 687633408. Its totient is φ = 390549600.

The previous prime is 521320253. The next prime is 521320301. The reversal of 521320261 is 162023125.

It is not a de Polignac number, because 521320261 - 2³ = 521320253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521329261) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1923556 + ... + 1923826.

It is an arithmetic number, because the mean of its divisors is an integer number (14325696).

Almost surely, 2^521320261 is an apocalyptic number.

It is an amenable number.

521320261 is a deficient number, since it is larger than the sum of its proper divisors (166313147).

521320261 is a wasteful number, since it uses less digits than its factorization.

521320261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 521320261 is about 22832.4387878299. The cubic root of 521320261 is about 804.8251416049.

Adding to 521320261 its reverse (162023125), we get a palindrome (683343386).

The spelling of 521320261 in words is "five hundred twenty-one million, three hundred twenty thousand, two hundred sixty-one".