21450971 has 2 divisors, whose sum is σ = 21450972. Its totient is φ = 21450970.

The previous prime is 21450959. The next prime is 21451007. The reversal of 21450971 is 17905412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21450971 - 2⁶ = 21450907 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21450901) 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, 10725485 + 10725486.

It is an arithmetic number, because the mean of its divisors is an integer number (10725486).

Almost surely, 2^21450971 is an apocalyptic number.

21450971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450971 is an equidigital number, since it uses as much as digits as its factorization.

21450971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21450971 is about 4631.5192971637. The cubic root of 21450971 is about 277.8533593381.

The spelling of 21450971 in words is "twenty-one million, four hundred fifty thousand, nine hundred seventy-one".