21797773 has 8 divisors (see below), whose sum is σ = 22934520. Its totient is φ = 20689920.

The previous prime is 21797771. The next prime is 21797779. The reversal of 21797773 is 37779712.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3161284 + 18636489 = 1778^2 + 4317^2 .

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 21797773 - 2¹ = 21797771 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 (21797771) 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 7 ways as a sum of consecutive naturals, for example, 5668 + ... + 8701.

It is an arithmetic number, because the mean of its divisors is an integer number (2866815).

Almost surely, 2^21797773 is an apocalyptic number.

It is an amenable number.

21797773 is a deficient number, since it is larger than the sum of its proper divisors (1136747).

21797773 is a wasteful number, since it uses less digits than its factorization.

21797773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14447.

The product of its digits is 129654, while the sum is 43.

The square root of 21797773 is about 4668.8085203829. The cubic root of 21797773 is about 279.3427313016.

The spelling of 21797773 in words is "twenty-one million, seven hundred ninety-seven thousand, seven hundred seventy-three".