21430193 has 2 divisors, whose sum is σ = 21430194. Its totient is φ = 21430192.

The previous prime is 21430177. The next prime is 21430229. The reversal of 21430193 is 39103412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19642624 + 1787569 = 4432^2 + 1337^2 .

It is a cyclic number.

It is not a de Polignac number, because 21430193 - 2⁴ = 21430177 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21430103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715096 + 10715097.

It is an arithmetic number, because the mean of its divisors is an integer number (10715097).

Almost surely, 2^21430193 is an apocalyptic number.

It is an amenable number.

21430193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21430193 is an equidigital number, since it uses as much as digits as its factorization.

21430193 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 21430193 is about 4629.2756452819. The cubic root of 21430193 is about 277.7636182234.

The spelling of 21430193 in words is "twenty-one million, four hundred thirty thousand, one hundred ninety-three".