21210193 has 2 divisors, whose sum is σ = 21210194. Its totient is φ = 21210192.

The previous prime is 21210179. The next prime is 21210197. The reversal of 21210193 is 39101212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15000129 + 6210064 = 3873^2 + 2492^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210193 - 2¹³ = 21202001 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210193.

It is not a weakly prime, because it can be changed into another prime (21210197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605096 + 10605097.

It is an arithmetic number, because the mean of its divisors is an integer number (10605097).

Almost surely, 2^21210193 is an apocalyptic number.

It is an amenable number.

21210193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210193 is an equidigital number, since it uses as much as digits as its factorization.

21210193 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21210193 is about 4605.4525293395. The cubic root of 21210193 is about 276.8098500802.

The spelling of 21210193 in words is "twenty-one million, two hundred ten thousand, one hundred ninety-three".