21340705 has 16 divisors (see below), whose sum is σ = 27619200. Its totient is φ = 15776640.

The previous prime is 21340663. The next prime is 21340721. The reversal of 21340705 is 50704312.

It is not a de Polignac number, because 21340705 - 2¹⁷ = 21209633 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1156 + ... + 6634.

It is an arithmetic number, because the mean of its divisors is an integer number (1726200).

Almost surely, 2^21340705 is an apocalyptic number.

It is an amenable number.

21340705 is a deficient number, since it is larger than the sum of its proper divisors (6278495).

21340705 is a wasteful number, since it uses less digits than its factorization.

21340705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5544.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21340705 is about 4619.6000909170. The cubic root of 21340705 is about 277.3764512377.

The spelling of 21340705 in words is "twenty-one million, three hundred forty thousand, seven hundred five".