21095705 has 8 divisors (see below), whose sum is σ = 25342152. Its totient is φ = 16858368.

The previous prime is 21095699. The next prime is 21095729. The reversal of 21095705 is 50759012.

It can be written as a sum of positive squares in 4 ways, for example, as 15768841 + 5326864 = 3971^2 + 2308^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21095705 - 2²⁰ = 20047129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4859 + ... + 8111.

It is an arithmetic number, because the mean of its divisors is an integer number (3167769).

Almost surely, 2^21095705 is an apocalyptic number.

It is an amenable number.

21095705 is a deficient number, since it is larger than the sum of its proper divisors (4246447).

21095705 is a wasteful number, since it uses less digits than its factorization.

21095705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4555.

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 21095705 is about 4593.0060962294. The cubic root of 21095705 is about 276.3108981718.

The spelling of 21095705 in words is "twenty-one million, ninety-five thousand, seven hundred five".