20215565101 has 4 divisors (see below), whose sum is σ = 20231396892. Its totient is φ = 20199733312.

The previous prime is 20215565089. The next prime is 20215565119. The reversal of 20215565101 is 10156551202.

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 16752124900 + 3463440201 = 129430^2 + 58851^2 .

It is a cyclic number.

It is not a de Polignac number, because 20215565101 - 2²⁵ = 20182010669 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20215565101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20215565141) 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, 7913980 + ... + 7916533.

It is an arithmetic number, because the mean of its divisors is an integer number (5057849223).

Almost surely, 2^20215565101 is an apocalyptic number.

It is an amenable number.

20215565101 is a deficient number, since it is larger than the sum of its proper divisors (15831791).

20215565101 is a wasteful number, since it uses less digits than its factorization.

20215565101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15831790.

The product of its (nonzero) digits is 3000, while the sum is 28.

The spelling of 20215565101 in words is "twenty billion, two hundred fifteen million, five hundred sixty-five thousand, one hundred one".