21316201 has 2 divisors, whose sum is σ = 21316202. Its totient is φ = 21316200.

The previous prime is 21316199. The next prime is 21316223. The reversal of 21316201 is 10261312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14288400 + 7027801 = 3780^2 + 2651^2 .

It is a cyclic number.

It is not a de Polignac number, because 21316201 - 2¹ = 21316199 is a prime.

Together with 21316199, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21316231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658100 + 10658101.

It is an arithmetic number, because the mean of its divisors is an integer number (10658101).

Almost surely, 2^21316201 is an apocalyptic number.

It is an amenable number.

21316201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21316201 is an equidigital number, since it uses as much as digits as its factorization.

21316201 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 21316201 is about 4616.9471515277. The cubic root of 21316201 is about 277.2702467541.

Adding to 21316201 its reverse (10261312), we get a palindrome (31577513).

The spelling of 21316201 in words is "twenty-one million, three hundred sixteen thousand, two hundred one".