21769889 has 6 divisors (see below), whose sum is σ = 21918246. Its totient is φ = 21622400.

The previous prime is 21769861. The next prime is 21769903. The reversal of 21769889 is 98896712.

It can be written as a sum of positive squares in 3 ways, for example, as 3579664 + 18190225 = 1892^2 + 4265^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21769889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21769829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54089 + ... + 54489.

It is an arithmetic number, because the mean of its divisors is an integer number (3653041).

Almost surely, 2^21769889 is an apocalyptic number.

It is an amenable number.

21769889 is a deficient number, since it is larger than the sum of its proper divisors (148357).

21769889 is an frugal number, since it uses more digits than its factorization.

21769889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867 (or 634 counting only the distinct ones).

The product of its digits is 435456, while the sum is 50.

The square root of 21769889 is about 4665.8213639187. The cubic root of 21769889 is about 279.2235675010.

The spelling of 21769889 in words is "twenty-one million, seven hundred sixty-nine thousand, eight hundred eighty-nine".