20575037561 has 4 divisors (see below), whose sum is σ = 22157732772. Its totient is φ = 18992342352.

The previous prime is 20575037521. The next prime is 20575037563. The reversal of 20575037561 is 16573057502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9629693161 + 10945344400 = 98131^2 + 104620^2 .

It is a cyclic number.

It is not a de Polignac number, because 20575037561 - 2³⁴ = 3395168377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20575037563) 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, 791347586 + ... + 791347611.

It is an arithmetic number, because the mean of its divisors is an integer number (5539433193).

Almost surely, 2^20575037561 is an apocalyptic number.

It is an amenable number.

20575037561 is a deficient number, since it is larger than the sum of its proper divisors (1582695211).

20575037561 is a wasteful number, since it uses less digits than its factorization.

20575037561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1582695210.

The product of its (nonzero) digits is 220500, while the sum is 41.

The spelling of 20575037561 in words is "twenty billion, five hundred seventy-five million, thirty-seven thousand, five hundred sixty-one".