20311101221 has 4 divisors (see below), whose sum is σ = 20312647500. Its totient is φ = 20309554944.

The previous prime is 20311101191. The next prime is 20311101247. The reversal of 20311101221 is 12210111302.

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 5110677121 + 15200424100 = 71489^2 + 123290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20311101221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20311101196 and 20311101205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311101281) 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, 753266 + ... + 779763.

It is an arithmetic number, because the mean of its divisors is an integer number (5078161875).

Almost surely, 2^20311101221 is an apocalyptic number.

It is an amenable number.

20311101221 is a deficient number, since it is larger than the sum of its proper divisors (1546279).

20311101221 is a wasteful number, since it uses less digits than its factorization.

20311101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1546278.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 20311101221 its reverse (12210111302), we get a palindrome (32521212523).

The spelling of 20311101221 in words is "twenty billion, three hundred eleven million, one hundred one thousand, two hundred twenty-one".