21799885 has 8 divisors (see below), whose sum is σ = 26190360. Its totient is φ = 17419584.

The previous prime is 21799879. The next prime is 21799889. The reversal of 21799885 is 58899712.

It can be written as a sum of positive squares in 4 ways, for example, as 7767369 + 14032516 = 2787^2 + 3746^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21799885 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21799889) 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, 3471 + ... + 7459.

It is an arithmetic number, because the mean of its divisors is an integer number (3273795).

Almost surely, 2^21799885 is an apocalyptic number.

It is an amenable number.

21799885 is a deficient number, since it is larger than the sum of its proper divisors (4390475).

21799885 is a wasteful number, since it uses less digits than its factorization.

21799885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5087.

The product of its digits is 362880, while the sum is 49.

The square root of 21799885 is about 4669.0346968083. The cubic root of 21799885 is about 279.3517529082.

The spelling of 21799885 in words is "twenty-one million, seven hundred ninety-nine thousand, eight hundred eighty-five".