21226687 has 2 divisors, whose sum is σ = 21226688. Its totient is φ = 21226686.

The previous prime is 21226663. The next prime is 21226703. The reversal of 21226687 is 78662212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21226687 - 2¹⁵ = 21193919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21226627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613343 + 10613344.

It is an arithmetic number, because the mean of its divisors is an integer number (10613344).

Almost surely, 2^21226687 is an apocalyptic number.

21226687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226687 is an equidigital number, since it uses as much as digits as its factorization.

21226687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 34.

The square root of 21226687 is about 4607.2428848499. The cubic root of 21226687 is about 276.8815847517.

Adding to 21226687 its reverse (78662212), we get a palindrome (99888899).

The spelling of 21226687 in words is "twenty-one million, two hundred twenty-six thousand, six hundred eighty-seven".