21224087 has 2 divisors, whose sum is σ = 21224088. Its totient is φ = 21224086.

The previous prime is 21224081. The next prime is 21224123. The reversal of 21224087 is 78042212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21224087 - 2⁶ = 21224023 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21224081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612043 + 10612044.

It is an arithmetic number, because the mean of its divisors is an integer number (10612044).

Almost surely, 2^21224087 is an apocalyptic number.

21224087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21224087 is an equidigital number, since it uses as much as digits as its factorization.

21224087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21224087 is about 4606.9607117925. The cubic root of 21224087 is about 276.8702794623.

Adding to 21224087 its reverse (78042212), we get a palindrome (99266299).

The spelling of 21224087 in words is "twenty-one million, two hundred twenty-four thousand, eighty-seven".