21426109 has 2 divisors, whose sum is σ = 21426110. Its totient is φ = 21426108.

The previous prime is 21426101. The next prime is 21426161. The reversal of 21426109 is 90162412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 2022084 = 4405^2 + 1422^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426109 - 2³ = 21426101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21426101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713054 + 10713055.

It is an arithmetic number, because the mean of its divisors is an integer number (10713055).

Almost surely, 2^21426109 is an apocalyptic number.

It is an amenable number.

21426109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426109 is an equidigital number, since it uses as much as digits as its factorization.

21426109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21426109 is about 4628.8345185370. The cubic root of 21426109 is about 277.7459724236.

The spelling of 21426109 in words is "twenty-one million, four hundred twenty-six thousand, one hundred nine".