21371101 has 2 divisors, whose sum is σ = 21371102. Its totient is φ = 21371100.

The previous prime is 21371099. The next prime is 21371107. The reversal of 21371101 is 10117312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17023876 + 4347225 = 4126^2 + 2085^2 .

It is a cyclic number.

It is not a de Polignac number, because 21371101 - 2¹ = 21371099 is a prime.

Together with 21371099, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21371107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10685550 + 10685551.

It is an arithmetic number, because the mean of its divisors is an integer number (10685551).

Almost surely, 2^21371101 is an apocalyptic number.

It is an amenable number.

21371101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21371101 is an equidigital number, since it uses as much as digits as its factorization.

21371101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42, while the sum is 16.

The square root of 21371101 is about 4622.8888154486. Note that the first 4 decimals coincide. The cubic root of 21371101 is about 277.5080797366.

Adding to 21371101 its reverse (10117312), we get a palindrome (31488413).

The spelling of 21371101 in words is "twenty-one million, three hundred seventy-one thousand, one hundred one".