21242101 has 2 divisors, whose sum is σ = 21242102. Its totient is φ = 21242100.

The previous prime is 21242093. The next prime is 21242131. The reversal of 21242101 is 10124212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21169201 + 72900 = 4601^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242101 - 2³ = 21242093 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21242131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621050 + 10621051.

It is an arithmetic number, because the mean of its divisors is an integer number (10621051).

Almost surely, 2^21242101 is an apocalyptic number.

It is an amenable number.

21242101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242101 is an equidigital number, since it uses as much as digits as its factorization.

21242101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21242101 is about 4608.9153821696. The cubic root of 21242101 is about 276.9485887722.

Adding to 21242101 its reverse (10124212), we get a palindrome (31366313).

It can be divided in two parts, 2124 and 2101, that added together give a square (4225 = 65²).

The spelling of 21242101 in words is "twenty-one million, two hundred forty-two thousand, one hundred one".