21195497 has 2 divisors, whose sum is σ = 21195498. Its totient is φ = 21195496.

The previous prime is 21195479. The next prime is 21195509. The reversal of 21195497 is 79459112.

Together with previous prime (21195479) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14167696 + 7027801 = 3764^2 + 2651^2 .

It is a cyclic number.

It is not a de Polignac number, because 21195497 - 2¹⁶ = 21129961 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21195497.

It is not a weakly prime, because it can be changed into another prime (21195437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10597748 + 10597749.

It is an arithmetic number, because the mean of its divisors is an integer number (10597749).

Almost surely, 2^21195497 is an apocalyptic number.

It is an amenable number.

21195497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21195497 is an equidigital number, since it uses as much as digits as its factorization.

21195497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 38.

The square root of 21195497 is about 4603.8567527672. The cubic root of 21195497 is about 276.7459038217.

The spelling of 21195497 in words is "twenty-one million, one hundred ninety-five thousand, four hundred ninety-seven".