21708801 has 6 divisors (see below), whose sum is σ = 31357170. Its totient is φ = 14472528.

The previous prime is 21708793. The next prime is 21708821. The reversal of 21708801 is 10880712.

It can be written as a sum of positive squares in only one way, i.e., 12852225 + 8856576 = 3585^2 + 2976^2 .

It is not a de Polignac number, because 21708801 - 2³ = 21708793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21708821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1206036 + ... + 1206053.

It is an arithmetic number, because the mean of its divisors is an integer number (5226195).

It is a Proth number, since it is equal to 1325 ⋅ 2¹⁴ + 1 and 1325 < 2¹⁴.

Almost surely, 2^21708801 is an apocalyptic number.

It is an amenable number.

21708801 is a deficient number, since it is larger than the sum of its proper divisors (9648369).

21708801 is a wasteful number, since it uses less digits than its factorization.

21708801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2412095 (or 2412092 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 21708801 is about 4659.2704364525. The cubic root of 21708801 is about 278.9621484858.

The spelling of 21708801 in words is "twenty-one million, seven hundred eight thousand, eight hundred one".