523021561 has 4 divisors (see below), whose sum is σ = 527014224. Its totient is φ = 519028900.

The previous prime is 523021559. The next prime is 523021579. The reversal of 523021561 is 165120325.

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 not a de Polignac number, because 523021561 - 2¹ = 523021559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (523021591) 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, 1996135 + ... + 1996396.

It is an arithmetic number, because the mean of its divisors is an integer number (131753556).

Almost surely, 2^523021561 is an apocalyptic number.

It is an amenable number.

523021561 is a deficient number, since it is larger than the sum of its proper divisors (3992663).

523021561 is a wasteful number, since it uses less digits than its factorization.

523021561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3992662.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 523021561 is about 22869.6646455518. The cubic root of 523021561 is about 805.6996918068.

Adding to 523021561 its reverse (165120325), we get a palindrome (688141886).

The spelling of 523021561 in words is "five hundred twenty-three million, twenty-one thousand, five hundred sixty-one".