21738789 has 12 divisors (see below), whose sum is σ = 31504876. Its totient is φ = 14444352.

The previous prime is 21738763. The next prime is 21738803. The reversal of 21738789 is 98783712.

It can be written as a sum of positive squares in 2 ways, for example, as 3744225 + 17994564 = 1935^2 + 4242^2 .

It is not a de Polignac number, because 21738789 - 2¹⁵ = 21706021 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 (21738089) 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 11 ways as a sum of consecutive naturals, for example, 1042 + ... + 6675.

Almost surely, 2^21738789 is an apocalyptic number.

It is an amenable number.

21738789 is a deficient number, since it is larger than the sum of its proper divisors (9766087).

21738789 is a wasteful number, since it uses less digits than its factorization.

21738789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8036 (or 8033 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 21738789 is about 4662.4874262565. The cubic root of 21738789 is about 279.0905398525.

The spelling of 21738789 in words is "twenty-one million, seven hundred thirty-eight thousand, seven hundred eighty-nine".