21266953 has 2 divisors, whose sum is σ = 21266954. Its totient is φ = 21266952.

The previous prime is 21266951. The next prime is 21266977. The reversal of 21266953 is 35966212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15468489 + 5798464 = 3933^2 + 2408^2 .

It is a cyclic number.

It is not a de Polignac number, because 21266953 - 2¹ = 21266951 is a prime.

Together with 21266951, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21266951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633476 + 10633477.

It is an arithmetic number, because the mean of its divisors is an integer number (10633477).

Almost surely, 2^21266953 is an apocalyptic number.

It is an amenable number.

21266953 is a deficient number, since it is larger than the sum of its proper divisors (1).

21266953 is an equidigital number, since it uses as much as digits as its factorization.

21266953 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 34.

The square root of 21266953 is about 4611.6106730729. The cubic root of 21266953 is about 277.0565511617.

The spelling of 21266953 in words is "twenty-one million, two hundred sixty-six thousand, nine hundred fifty-three".