561333521 has 4 divisors (see below), whose sum is σ = 641524032. Its totient is φ = 481143012.

The previous prime is 561333517. The next prime is 561333629. The reversal of 561333521 is 125333165.

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, and also an emirpimes, since its reverse is a distinct semiprime: 125333165 = 5 ⋅25066633.

It is not a de Polignac number, because 561333521 - 2² = 561333517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (561333221) 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, 40095245 + ... + 40095258.

It is an arithmetic number, because the mean of its divisors is an integer number (160381008).

Almost surely, 2^561333521 is an apocalyptic number.

It is an amenable number.

561333521 is a deficient number, since it is larger than the sum of its proper divisors (80190511).

561333521 is an equidigital number, since it uses as much as digits as its factorization.

561333521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80190510.

The product of its digits is 8100, while the sum is 29.

The square root of 561333521 is about 23692.4781523588. The cubic root of 561333521 is about 824.9108056617.

Adding to 561333521 its reverse (125333165), we get a palindrome (686666686).

The spelling of 561333521 in words is "five hundred sixty-one million, three hundred thirty-three thousand, five hundred twenty-one".