21204442101 has 4 divisors (see below), whose sum is σ = 28272589472. Its totient is φ = 14136294732.

The previous prime is 21204442087. The next prime is 21204442183. The reversal of 21204442101 is 10124440212.

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.

It is not a de Polignac number, because 21204442101 - 2¹³ = 21204433909 is a prime.

It is a super-2 number, since 2×21204442101² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204442001) 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, 3534073681 + ... + 3534073686.

It is an arithmetic number, because the mean of its divisors is an integer number (7068147368).

Almost surely, 2^21204442101 is an apocalyptic number.

It is an amenable number.

21204442101 is a deficient number, since it is larger than the sum of its proper divisors (7068147371).

21204442101 is an equidigital number, since it uses as much as digits as its factorization.

21204442101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7068147370.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21204442101 its reverse (10124440212), we get a palindrome (31328882313).

The spelling of 21204442101 in words is "twenty-one billion, two hundred four million, four hundred forty-two thousand, one hundred one".