21568801 has 4 divisors (see below), whose sum is σ = 22837572. Its totient is φ = 20300032.

The previous prime is 21568787. The next prime is 21568831. The reversal of 21568801 is 10886512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7700625 + 13868176 = 2775^2 + 3724^2 .

It is a cyclic number.

It is not a de Polignac number, because 21568801 - 2⁹ = 21568289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21568831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 634360 + ... + 634393.

It is an arithmetic number, because the mean of its divisors is an integer number (5709393).

Almost surely, 2^21568801 is an apocalyptic number.

It is an amenable number.

21568801 is a deficient number, since it is larger than the sum of its proper divisors (1268771).

21568801 is a wasteful number, since it uses less digits than its factorization.

21568801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1268770.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 21568801 is about 4644.2223245663. Note that the first 3 decimals coincide. The cubic root of 21568801 is about 278.3611793607.

The spelling of 21568801 in words is "twenty-one million, five hundred sixty-eight thousand, eight hundred one".