21236101 has 2 divisors, whose sum is σ = 21236102. Its totient is φ = 21236100.

The previous prime is 21236099. The next prime is 21236123. The reversal of 21236101 is 10163212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15992001 + 5244100 = 3999^2 + 2290^2 .

It is a cyclic number.

It is not a de Polignac number, because 21236101 - 2¹ = 21236099 is a prime.

Together with 21236099, it forms a pair of twin primes.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21236141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10618050 + 10618051.

It is an arithmetic number, because the mean of its divisors is an integer number (10618051).

Almost surely, 2^21236101 is an apocalyptic number.

It is an amenable number.

21236101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21236101 is an equidigital number, since it uses as much as digits as its factorization.

21236101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21236101 is about 4608.2644238368. The cubic root of 21236101 is about 276.9225108745.

Adding to 21236101 its reverse (10163212), we get a palindrome (31399313).

The spelling of 21236101 in words is "twenty-one million, two hundred thirty-six thousand, one hundred one".