21349187 has 2 divisors, whose sum is σ = 21349188. Its totient is φ = 21349186.

The previous prime is 21349183. The next prime is 21349189. The reversal of 21349187 is 78194312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21349187 - 2² = 21349183 is a prime.

Together with 21349189, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21349183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10674593 + 10674594.

It is an arithmetic number, because the mean of its divisors is an integer number (10674594).

Almost surely, 2^21349187 is an apocalyptic number.

21349187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21349187 is an equidigital number, since it uses as much as digits as its factorization.

21349187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 35.

The square root of 21349187 is about 4620.5180445487. The cubic root of 21349187 is about 277.4131947196.

The spelling of 21349187 in words is "twenty-one million, three hundred forty-nine thousand, one hundred eighty-seven".