21405127 has 2 divisors, whose sum is σ = 21405128. Its totient is φ = 21405126.

The previous prime is 21405121. The next prime is 21405149. The reversal of 21405127 is 72150412.

It is a happy number.

It is an a-pointer prime, because the next prime (21405149) can be obtained adding 21405127 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21405127 - 2¹¹ = 21403079 is a prime.

It is a super-2 number, since 2×21405127² = 916358923772258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21405098 and 21405107.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21405121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10702563 + 10702564.

It is an arithmetic number, because the mean of its divisors is an integer number (10702564).

Almost surely, 2^21405127 is an apocalyptic number.

21405127 is a deficient number, since it is larger than the sum of its proper divisors (1).

21405127 is an equidigital number, since it uses as much as digits as its factorization.

21405127 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21405127 is about 4626.5675181499. The cubic root of 21405127 is about 277.6552798124.

Adding to 21405127 its reverse (72150412), we get a palindrome (93555539).

The spelling of 21405127 in words is "twenty-one million, four hundred five thousand, one hundred twenty-seven".