21021001101 has 24 divisors (see below), whose sum is σ = 31969080000. Its totient is φ = 13273379712.

The previous prime is 21021001097. The next prime is 21021001123. The reversal of 21021001101 is 10110012012.

It is a happy number.

It is not a de Polignac number, because 21021001101 - 2² = 21021001097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021001171) 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 23 ways as a sum of consecutive naturals, for example, 911845 + ... + 934613.

It is an arithmetic number, because the mean of its divisors is an integer number (1332045000).

Almost surely, 2^21021001101 is an apocalyptic number.

It is an amenable number.

21021001101 is a deficient number, since it is larger than the sum of its proper divisors (10948078899).

21021001101 is a wasteful number, since it uses less digits than its factorization.

21021001101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28193 (or 28190 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21021001101 its reverse (10110012012), we get a palindrome (31131013113).

The spelling of 21021001101 in words is "twenty-one billion, twenty-one million, one thousand, one hundred one".