21412789 has 2 divisors, whose sum is σ = 21412790. Its totient is φ = 21412788.

The previous prime is 21412739. The next prime is 21412799. The reversal of 21412789 is 98721412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21316689 + 96100 = 4617^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 21412789 - 2⁹ = 21412277 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21412739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10706394 + 10706395.

It is an arithmetic number, because the mean of its divisors is an integer number (10706395).

Almost surely, 2^21412789 is an apocalyptic number.

It is an amenable number.

21412789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21412789 is an equidigital number, since it uses as much as digits as its factorization.

21412789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 34.

The square root of 21412789 is about 4627.3954877447. The cubic root of 21412789 is about 277.6884049132.

It can be divided in two parts, 21412 and 789, that added together give a square (22201 = 149²).

The spelling of 21412789 in words is "twenty-one million, four hundred twelve thousand, seven hundred eighty-nine".