21795811 has 4 divisors (see below), whose sum is σ = 21873112. Its totient is φ = 21718512.

The previous prime is 21795757. The next prime is 21795817. The reversal of 21795811 is 11859712.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21795811 - 2¹¹ = 21793763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21795817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38226 + ... + 38791.

It is an arithmetic number, because the mean of its divisors is an integer number (5468278).

Almost surely, 2^21795811 is an apocalyptic number.

21795811 is a deficient number, since it is larger than the sum of its proper divisors (77301).

21795811 is an equidigital number, since it uses as much as digits as its factorization.

21795811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77300.

The product of its digits is 5040, while the sum is 34.

The square root of 21795811 is about 4668.5983978063. The cubic root of 21795811 is about 279.3343499120.

The spelling of 21795811 in words is "twenty-one million, seven hundred ninety-five thousand, eight hundred eleven".