21986329 has 2 divisors, whose sum is σ = 21986330. Its totient is φ = 21986328.

The previous prime is 21986323. The next prime is 21986333. The reversal of 21986329 is 92368912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20720704 + 1265625 = 4552^2 + 1125^2 .

It is a cyclic number.

It is not a de Polignac number, because 21986329 - 2¹³ = 21978137 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21986291 and 21986300.

It is not a weakly prime, because it can be changed into another prime (21986323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10993164 + 10993165.

It is an arithmetic number, because the mean of its divisors is an integer number (10993165).

Almost surely, 2^21986329 is an apocalyptic number.

It is an amenable number.

21986329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21986329 is an equidigital number, since it uses as much as digits as its factorization.

21986329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 40.

The square root of 21986329 is about 4688.9581998563. The cubic root of 21986329 is about 280.1458806153.

The spelling of 21986329 in words is "twenty-one million, nine hundred eighty-six thousand, three hundred twenty-nine".