21641101 has 4 divisors (see below), whose sum is σ = 21651100. Its totient is φ = 21631104.

The previous prime is 21641099. The next prime is 21641107. The reversal of 21641101 is 10114612.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15015625 + 6625476 = 3875^2 + 2574^2 .

It is a cyclic number.

It is not a de Polignac number, because 21641101 - 2¹ = 21641099 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246 + ... + 6583.

It is an arithmetic number, because the mean of its divisors is an integer number (5412775).

Almost surely, 2^21641101 is an apocalyptic number.

It is an amenable number.

21641101 is a deficient number, since it is larger than the sum of its proper divisors (9999).

21641101 is an equidigital number, since it uses as much as digits as its factorization.

21641101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9998.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 21641101 is about 4651.9996775580. Note that the first 3 decimals coincide. The cubic root of 21641101 is about 278.6718606347.

Adding to 21641101 its reverse (10114612), we get a palindrome (31755713).

The spelling of 21641101 in words is "twenty-one million, six hundred forty-one thousand, one hundred one".