520961561 has 4 divisors (see below), whose sum is σ = 521102352. Its totient is φ = 520820772.

The previous prime is 520961531. The next prime is 520961599. The reversal of 520961561 is 165169025.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-520961561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (520961521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64691 + ... + 72296.

It is an arithmetic number, because the mean of its divisors is an integer number (130275588).

Almost surely, 2^520961561 is an apocalyptic number.

It is an amenable number.

520961561 is a deficient number, since it is larger than the sum of its proper divisors (140791).

520961561 is a wasteful number, since it uses less digits than its factorization.

520961561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140790.

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 520961561 is about 22824.5823839123. The cubic root of 520961561 is about 804.6405097273.

The spelling of 520961561 in words is "five hundred twenty million, nine hundred sixty-one thousand, five hundred sixty-one".