21094609 has 2 divisors, whose sum is σ = 21094610. Its totient is φ = 21094608.

The previous prime is 21094589. The next prime is 21094627. The reversal of 21094609 is 90649012.

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., 18835600 + 2259009 = 4340^2 + 1503^2 .

It is a cyclic number.

It is not a de Polignac number, because 21094609 - 2⁹ = 21094097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21094649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10547304 + 10547305.

It is an arithmetic number, because the mean of its divisors is an integer number (10547305).

Almost surely, 2^21094609 is an apocalyptic number.

It is an amenable number.

21094609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21094609 is an equidigital number, since it uses as much as digits as its factorization.

21094609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21094609 is about 4592.8867828415. The cubic root of 21094609 is about 276.3061129641.

The spelling of 21094609 in words is "twenty-one million, ninety-four thousand, six hundred nine".