21220122001 has 4 divisors (see below), whose sum is σ = 22852439092. Its totient is φ = 19587804912.

The previous prime is 21220121971. The next prime is 21220122029. The reversal of 21220122001 is 10022102212.

It is a happy number.

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 6076358401 + 15143763600 = 77951^2 + 123060^2 .

It is not a de Polignac number, because 21220122001 - 2⁵ = 21220121969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1632317077 = 21220122001 / (2 + 1 + 2 + 2 + 0 + 1 + 2 + 2 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220122101) 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, 816158526 + ... + 816158551.

It is an arithmetic number, because the mean of its divisors is an integer number (5713109773).

Almost surely, 2^21220122001 is an apocalyptic number.

It is an amenable number.

21220122001 is a deficient number, since it is larger than the sum of its proper divisors (1632317091).

21220122001 is a wasteful number, since it uses less digits than its factorization.

21220122001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632317090.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21220122001 its reverse (10022102212), we get a palindrome (31242224213).

The spelling of 21220122001 in words is "twenty-one billion, two hundred twenty million, one hundred twenty-two thousand, one".