21226451 has 2 divisors, whose sum is σ = 21226452. Its totient is φ = 21226450.

The previous prime is 21226441. The next prime is 21226453. The reversal of 21226451 is 15462212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21226451 is a prime.

Together with 21226453, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21226453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613225 + 10613226.

It is an arithmetic number, because the mean of its divisors is an integer number (10613226).

Almost surely, 2^21226451 is an apocalyptic number.

21226451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226451 is an equidigital number, since it uses as much as digits as its factorization.

21226451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 960, while the sum is 23.

The square root of 21226451 is about 4607.2172729317. The cubic root of 21226451 is about 276.8805586174.

Adding to 21226451 its reverse (15462212), we get a palindrome (36688663).

The spelling of 21226451 in words is "twenty-one million, two hundred twenty-six thousand, four hundred fifty-one".