21321101 has 2 divisors, whose sum is σ = 21321102. Its totient is φ = 21321100.

The previous prime is 21321089. The next prime is 21321121. The reversal of 21321101 is 10112312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13764100 + 7557001 = 3710^2 + 2749^2 .

It is a cyclic number.

It is not a de Polignac number, because 21321101 - 2²² = 17126797 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21321121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660550 + 10660551.

It is an arithmetic number, because the mean of its divisors is an integer number (10660551).

Almost surely, 2^21321101 is an apocalyptic number.

It is an amenable number.

21321101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321101 is an equidigital number, since it uses as much as digits as its factorization.

21321101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 21321101 is about 4617.4777747164. The cubic root of 21321101 is about 277.2914906915.

Adding to 21321101 its reverse (10112312), we get a palindrome (31433413).

The spelling of 21321101 in words is "twenty-one million, three hundred twenty-one thousand, one hundred one".