21650087 has 2 divisors, whose sum is σ = 21650088. Its totient is φ = 21650086.

The previous prime is 21650021. The next prime is 21650089. The reversal of 21650087 is 78005612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21650087 - 2²² = 17455783 is a prime.

Together with 21650089, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21650089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825043 + 10825044.

It is an arithmetic number, because the mean of its divisors is an integer number (10825044).

Almost surely, 2^21650087 is an apocalyptic number.

21650087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21650087 is an equidigital number, since it uses as much as digits as its factorization.

21650087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 21650087 is about 4652.9653985389. The cubic root of 21650087 is about 278.7104261220.

Adding to 21650087 its reverse (78005612), we get a palindrome (99655699).

The spelling of 21650087 in words is "twenty-one million, six hundred fifty thousand, eighty-seven".