21476789 has 2 divisors, whose sum is σ = 21476790. Its totient is φ = 21476788.

The previous prime is 21476773. The next prime is 21476801. The reversal of 21476789 is 98767412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21464689 + 12100 = 4633^2 + 110^2 .

It is a cyclic number.

It is not a de Polignac number, because 21476789 - 2⁴ = 21476773 is a prime.

It is a super-2 number, since 2×21476789² = 922504931501042, which contains 22 as substring.

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 (21476489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10738394 + 10738395.

It is an arithmetic number, because the mean of its divisors is an integer number (10738395).

Almost surely, 2^21476789 is an apocalyptic number.

It is an amenable number.

21476789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21476789 is an equidigital number, since it uses as much as digits as its factorization.

21476789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 44.

The square root of 21476789 is about 4634.3056653613. The cubic root of 21476789 is about 277.9647877351.

The spelling of 21476789 in words is "twenty-one million, four hundred seventy-six thousand, seven hundred eighty-nine".