21427065 has 64 divisors (see below), whose sum is σ = 42577920. Its totient is φ = 10134720.

The previous prime is 21427039. The next prime is 21427073. The reversal of 21427065 is 56072412.

It is not a de Polignac number, because 21427065 - 2⁸ = 21426809 is a prime.

It is a super-2 number, since 2×21427065² = 918238229028450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 69642 + ... + 69948.

It is an arithmetic number, because the mean of its divisors is an integer number (665280).

Almost surely, 2^21427065 is an apocalyptic number.

It is an amenable number.

21427065 is a deficient number, since it is larger than the sum of its proper divisors (21150855).

21427065 is a wasteful number, since it uses less digits than its factorization.

21427065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21427065 is about 4628.9377831204. The cubic root of 21427065 is about 277.7501032281.

Adding to 21427065 its reverse (56072412), we get a palindrome (77499477).

The spelling of 21427065 in words is "twenty-one million, four hundred twenty-seven thousand, sixty-five".