20506220616211 has 4 divisors (see below), whose sum is σ = 22370422490424. Its totient is φ = 18642018742000.

The previous prime is 20506220616139. The next prime is 20506220616281. The reversal of 20506220616211 is 11261602260502.

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

It is a cyclic number.

It is not a de Polignac number, because 20506220616211 - 2¹³ = 20506220608019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20506220616281) 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, 932100937090 + ... + 932100937111.

It is an arithmetic number, because the mean of its divisors is an integer number (5592605622606).

Almost surely, 2^{20506220616211} is an apocalyptic number.

20506220616211 is a deficient number, since it is larger than the sum of its proper divisors (1864201874213).

20506220616211 is a wasteful number, since it uses less digits than its factorization.

20506220616211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1864201874212.

The product of its (nonzero) digits is 17280, while the sum is 34.

Adding to 20506220616211 its reverse (11261602260502), we get a palindrome (31767822876713).

The spelling of 20506220616211 in words is "twenty trillion, five hundred six billion, two hundred twenty million, six hundred sixteen thousand, two hundred eleven".