21358429 has 2 divisors, whose sum is σ = 21358430. Its totient is φ = 21358428.

The previous prime is 21358399. The next prime is 21358439. The reversal of 21358429 is 92485312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 1954404 = 4405^2 + 1398^2 .

It is a cyclic number.

It is not a de Polignac number, because 21358429 - 2⁵ = 21358397 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21358394 and 21358403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21358439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10679214 + 10679215.

It is an arithmetic number, because the mean of its divisors is an integer number (10679215).

Almost surely, 2^21358429 is an apocalyptic number.

It is an amenable number.

21358429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21358429 is an equidigital number, since it uses as much as digits as its factorization.

21358429 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 34.

The square root of 21358429 is about 4621.5180406442. The cubic root of 21358429 is about 277.4532193956.

The spelling of 21358429 in words is "twenty-one million, three hundred fifty-eight thousand, four hundred twenty-nine".