21316369 has 2 divisors, whose sum is σ = 21316370. Its totient is φ = 21316368.

The previous prime is 21316349. The next prime is 21316391. The reversal of 21316369 is 96361312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20657025 + 659344 = 4545^2 + 812^2 .

It is a cyclic number.

It is not a de Polignac number, because 21316369 - 2²¹ = 19219217 is a prime.

It is a super-2 number, since 2×21316369² = 908775174688322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21316369.

It is not a weakly prime, because it can be changed into another prime (21316319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658184 + 10658185.

It is an arithmetic number, because the mean of its divisors is an integer number (10658185).

Almost surely, 2^21316369 is an apocalyptic number.

It is an amenable number.

21316369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21316369 is an equidigital number, since it uses as much as digits as its factorization.

21316369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 31.

The square root of 21316369 is about 4616.9653453324. The cubic root of 21316369 is about 277.2709751716.

The spelling of 21316369 in words is "twenty-one million, three hundred sixteen thousand, three hundred sixty-nine".