20566603501 has 4 divisors (see below), whose sum is σ = 20567089600. Its totient is φ = 20566117404.

The previous prime is 20566603493. The next prime is 20566603517. The reversal of 20566603501 is 10530666502.

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: 10530666502 = 2 ⋅5265333251.

It is a cyclic number.

It is not a de Polignac number, because 20566603501 - 2³ = 20566603493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20566603571) 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, 172821 + ... + 266458.

It is an arithmetic number, because the mean of its divisors is an integer number (5141772400).

Almost surely, 2^20566603501 is an apocalyptic number.

It is an amenable number.

20566603501 is a deficient number, since it is larger than the sum of its proper divisors (486099).

20566603501 is an equidigital number, since it uses as much as digits as its factorization.

20566603501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486098.

The product of its (nonzero) digits is 32400, while the sum is 34.

The spelling of 20566603501 in words is "twenty billion, five hundred sixty-six million, six hundred three thousand, five hundred one".