21900953 has 2 divisors, whose sum is σ = 21900954. Its totient is φ = 21900952.

The previous prime is 21900937. The next prime is 21900997. The reversal of 21900953 is 35900912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11641744 + 10259209 = 3412^2 + 3203^2 .

It is a cyclic number.

It is not a de Polignac number, because 21900953 - 2⁴ = 21900937 is a prime.

It is not a weakly prime, because it can be changed into another prime (21900253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950476 + 10950477.

It is an arithmetic number, because the mean of its divisors is an integer number (10950477).

Almost surely, 2^21900953 is an apocalyptic number.

It is an amenable number.

21900953 is a deficient number, since it is larger than the sum of its proper divisors (1).

21900953 is an equidigital number, since it uses as much as digits as its factorization.

21900953 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 21900953 is about 4679.8454034295. The cubic root of 21900953 is about 279.7827949860.

The spelling of 21900953 in words is "twenty-one million, nine hundred thousand, nine hundred fifty-three".