20051561533 has 4 divisors (see below), whose sum is σ = 20135459520. Its totient is φ = 19967663548.

The previous prime is 20051561527. The next prime is 20051561573. The reversal of 20051561533 is 33516515002.

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-20051561533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20051561495 and 20051561504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20051561573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41948635 + ... + 41949112.

It is an arithmetic number, because the mean of its divisors is an integer number (5033864880).

Almost surely, 2^20051561533 is an apocalyptic number.

It is an amenable number.

20051561533 is a deficient number, since it is larger than the sum of its proper divisors (83897987).

20051561533 is an equidigital number, since it uses as much as digits as its factorization.

20051561533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83897986.

The product of its (nonzero) digits is 13500, while the sum is 31.

The spelling of 20051561533 in words is "twenty billion, fifty-one million, five hundred sixty-one thousand, five hundred thirty-three".