21450929 has 2 divisors, whose sum is σ = 21450930. Its totient is φ = 21450928.

The previous prime is 21450917. The next prime is 21450931. The reversal of 21450929 is 92905412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14938225 + 6512704 = 3865^2 + 2552^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450929 is a prime.

Together with 21450931, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21450895 and 21450904.

It is not a weakly prime, because it can be changed into another prime (21450959) 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, 10725464 + 10725465.

It is an arithmetic number, because the mean of its divisors is an integer number (10725465).

Almost surely, 2^21450929 is an apocalyptic number.

It is an amenable number.

21450929 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450929 is an equidigital number, since it uses as much as digits as its factorization.

21450929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 21450929 is about 4631.5147630122. The cubic root of 21450929 is about 277.8531779966.

The spelling of 21450929 in words is "twenty-one million, four hundred fifty thousand, nine hundred twenty-nine".