21610187 has 2 divisors, whose sum is σ = 21610188. Its totient is φ = 21610186.

The previous prime is 21610151. The next prime is 21610217. The reversal of 21610187 is 78101612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21610187 - 2¹⁸ = 21348043 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21610387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10805093 + 10805094.

It is an arithmetic number, because the mean of its divisors is an integer number (10805094).

Almost surely, 2^21610187 is an apocalyptic number.

21610187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21610187 is an equidigital number, since it uses as much as digits as its factorization.

21610187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 21610187 is about 4648.6758329658. The cubic root of 21610187 is about 278.5391044927.

Adding to 21610187 its reverse (78101612), we get a palindrome (99711799).

The spelling of 21610187 in words is "twenty-one million, six hundred ten thousand, one hundred eighty-seven".