21158329 has 2 divisors, whose sum is σ = 21158330. Its totient is φ = 21158328.

The previous prime is 21158323. The next prime is 21158377. The reversal of 21158329 is 92385112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11868025 + 9290304 = 3445^2 + 3048^2 .

It is a cyclic number.

It is not a de Polignac number, because 21158329 - 2⁷ = 21158201 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21158329.

It is not a weakly prime, because it can be changed into another prime (21158323) 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 as a sum of consecutive naturals, namely, 10579164 + 10579165.

It is an arithmetic number, because the mean of its divisors is an integer number (10579165).

Almost surely, 2^21158329 is an apocalyptic number.

It is an amenable number.

21158329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21158329 is an equidigital number, since it uses as much as digits as its factorization.

21158329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 21158329 is about 4599.8183659792. The cubic root of 21158329 is about 276.5840438110.

The spelling of 21158329 in words is "twenty-one million, one hundred fifty-eight thousand, three hundred twenty-nine".