21012202100221 has 8 divisors (see below), whose sum is σ = 21112047948600. Its totient is φ = 20912426595840.

The previous prime is 21012202100209. The next prime is 21012202100249. The reversal of 21012202100221 is 12200120221012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10488594732100 + 10523607368121 = 3238610^2 + 3244011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21012202100221 - 2⁵ = 21012202100189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012202100195 and 21012202100204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012202100251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16987120 + ... + 18182041.

It is an arithmetic number, because the mean of its divisors is an integer number (2639005993575).

Almost surely, 2^{21012202100221} is an apocalyptic number.

It is an amenable number.

21012202100221 is a deficient number, since it is larger than the sum of its proper divisors (99845848379).

21012202100221 is a wasteful number, since it uses less digits than its factorization.

21012202100221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35171999.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21012202100221 its reverse (12200120221012), we get a palindrome (33212322321233).

The spelling of 21012202100221 in words is "twenty-one trillion, twelve billion, two hundred two million, one hundred thousand, two hundred twenty-one".