21012193 has 2 divisors, whose sum is σ = 21012194. Its totient is φ = 21012192.

The previous prime is 21012181. The next prime is 21012227. The reversal of 21012193 is 39121012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10975969 + 10036224 = 3313^2 + 3168^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012193 - 2⁵ = 21012161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21012193.

It is not a weakly prime, because it can be changed into another prime (21010193) 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, 10506096 + 10506097.

It is an arithmetic number, because the mean of its divisors is an integer number (10506097).

Almost surely, 2^21012193 is an apocalyptic number.

It is an amenable number.

21012193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012193 is an equidigital number, since it uses as much as digits as its factorization.

21012193 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21012193 is about 4583.9058672708. The cubic root of 21012193 is about 275.9458034381.

It can be divided in two parts, 210 and 12193, that added together give a triangular number (12403 = T₁₅₇).

The spelling of 21012193 in words is "twenty-one million, twelve thousand, one hundred ninety-three".