21293953 has 2 divisors, whose sum is σ = 21293954. Its totient is φ = 21293952.

The previous prime is 21293947. The next prime is 21293957. The reversal of 21293953 is 35939212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21270544 + 23409 = 4612^2 + 153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21293953 is a prime.

It is not a weakly prime, because it can be changed into another prime (21293957) 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, 10646976 + 10646977.

It is an arithmetic number, because the mean of its divisors is an integer number (10646977).

Almost surely, 2^21293953 is an apocalyptic number.

It is an amenable number.

21293953 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293953 is an equidigital number, since it uses as much as digits as its factorization.

21293953 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14580, while the sum is 34.

The square root of 21293953 is about 4614.5371382187. The cubic root of 21293953 is about 277.1737496372.

The spelling of 21293953 in words is "twenty-one million, two hundred ninety-three thousand, nine hundred fifty-three".