21101022001 has 4 divisors (see below), whose sum is σ = 21120762100. Its totient is φ = 21081281904.

The previous prime is 21101021987. The next prime is 21101022011. The reversal of 21101022001 is 10022010112.

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 16275635776 + 4825386225 = 127576^2 + 69465^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101022001 - 2⁹ = 21101021489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101022011) 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, 9868446 + ... + 9870583.

It is an arithmetic number, because the mean of its divisors is an integer number (5280190525).

Almost surely, 2^21101022001 is an apocalyptic number.

It is an amenable number.

21101022001 is a deficient number, since it is larger than the sum of its proper divisors (19740099).

21101022001 is a wasteful number, since it uses less digits than its factorization.

21101022001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19740098.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21101022001 its reverse (10022010112), we get a palindrome (31123032113).

The spelling of 21101022001 in words is "twenty-one billion, one hundred one million, twenty-two thousand, one".