21214087 has 2 divisors, whose sum is σ = 21214088. Its totient is φ = 21214086.

The previous prime is 21214049. The next prime is 21214111. The reversal of 21214087 is 78041212.

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-21214087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21214187) 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, 10607043 + 10607044.

It is an arithmetic number, because the mean of its divisors is an integer number (10607044).

Almost surely, 2^21214087 is an apocalyptic number.

21214087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21214087 is an equidigital number, since it uses as much as digits as its factorization.

21214087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21214087 is about 4605.8752696963. The cubic root of 21214087 is about 276.8267889737.

Adding to 21214087 its reverse (78041212), we get a palindrome (99255299).

The spelling of 21214087 in words is "twenty-one million, two hundred fourteen thousand, eighty-seven".