21048805 has 8 divisors (see below), whose sum is σ = 26744472. Its totient is φ = 15848448.

The previous prime is 21048803. The next prime is 21048829. The reversal of 21048805 is 50884012.

It can be written as a sum of positive squares in 4 ways, for example, as 2377764 + 18671041 = 1542^2 + 4321^2 .

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 21048805 - 2¹ = 21048803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21048803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123732 + ... + 123901.

It is an arithmetic number, because the mean of its divisors is an integer number (3343059).

Almost surely, 2^21048805 is an apocalyptic number.

It is an amenable number.

21048805 is a deficient number, since it is larger than the sum of its proper divisors (5695667).

21048805 is a wasteful number, since it uses less digits than its factorization.

21048805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247655.

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 21048805 is about 4587.8976666879. The cubic root of 21048805 is about 276.1059813182.

The spelling of 21048805 in words is "twenty-one million, forty-eight thousand, eight hundred five".