21413665 has 32 divisors (see below), whose sum is σ = 33304320. Its totient is φ = 12835584.

The previous prime is 21413647. The next prime is 21413677. The reversal of 21413665 is 56631412.

It is a cyclic number.

It is not a de Polignac number, because 21413665 - 2¹¹ = 21411617 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7407 + ... + 9883.

It is an arithmetic number, because the mean of its divisors is an integer number (1040760).

Almost surely, 2^21413665 is an apocalyptic number.

It is an amenable number.

21413665 is a deficient number, since it is larger than the sum of its proper divisors (11890655).

21413665 is a wasteful number, since it uses less digits than its factorization.

21413665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2521.

The product of its digits is 4320, while the sum is 28.

The square root of 21413665 is about 4627.4901404541. The cubic root of 21413665 is about 277.6921916179.

The spelling of 21413665 in words is "twenty-one million, four hundred thirteen thousand, six hundred sixty-five".