21520193 has 2 divisors, whose sum is σ = 21520194. Its totient is φ = 21520192.

The previous prime is 21520189. The next prime is 21520207. The reversal of 21520193 is 39102512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11641744 + 9878449 = 3412^2 + 3143^2 .

It is a cyclic number.

It is not a de Polignac number, because 21520193 - 2² = 21520189 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21520133) 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, 10760096 + 10760097.

It is an arithmetic number, because the mean of its divisors is an integer number (10760097).

Almost surely, 2^21520193 is an apocalyptic number.

It is an amenable number.

21520193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21520193 is an equidigital number, since it uses as much as digits as its factorization.

21520193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21520193 is about 4638.9862039027. The cubic root of 21520193 is about 278.1519147963.

The spelling of 21520193 in words is "twenty-one million, five hundred twenty thousand, one hundred ninety-three".