21365497 has 2 divisors, whose sum is σ = 21365498. Its totient is φ = 21365496.

The previous prime is 21365441. The next prime is 21365501. The reversal of 21365497 is 79456312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19678096 + 1687401 = 4436^2 + 1299^2 .

It is a cyclic number.

It is not a de Polignac number, because 21365497 - 2¹¹ = 21363449 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21363497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682748 + 10682749.

It is an arithmetic number, because the mean of its divisors is an integer number (10682749).

Almost surely, 2^21365497 is an apocalyptic number.

It is an amenable number.

21365497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365497 is an equidigital number, since it uses as much as digits as its factorization.

21365497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 37.

The square root of 21365497 is about 4622.2826611967. The cubic root of 21365497 is about 277.4838212573.

The spelling of 21365497 in words is "twenty-one million, three hundred sixty-five thousand, four hundred ninety-seven".