21412387 has 2 divisors, whose sum is σ = 21412388. Its totient is φ = 21412386.

The previous prime is 21412357. The next prime is 21412429. The reversal of 21412387 is 78321412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21412387 - 2¹¹ = 21410339 is a prime.

It is a super-3 number, since 3×21412387³ (a number of 23 digits) contains 333 as substring.

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 (21412337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10706193 + 10706194.

It is an arithmetic number, because the mean of its divisors is an integer number (10706194).

Almost surely, 2^21412387 is an apocalyptic number.

21412387 is a deficient number, since it is larger than the sum of its proper divisors (1).

21412387 is an equidigital number, since it uses as much as digits as its factorization.

21412387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 28.

The square root of 21412387 is about 4627.3520505793. The cubic root of 21412387 is about 277.6866671443.

Adding to 21412387 its reverse (78321412), we get a palindrome (99733799).

The spelling of 21412387 in words is "twenty-one million, four hundred twelve thousand, three hundred eighty-seven".