21094421 has 2 divisors, whose sum is σ = 21094422. Its totient is φ = 21094420.

The previous prime is 21094417. The next prime is 21094457. The reversal of 21094421 is 12449012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20124196 + 970225 = 4486^2 + 985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21094421 - 2² = 21094417 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21094721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10547210 + 10547211.

It is an arithmetic number, because the mean of its divisors is an integer number (10547211).

Almost surely, 2^21094421 is an apocalyptic number.

It is an amenable number.

21094421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21094421 is an equidigital number, since it uses as much as digits as its factorization.

21094421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21094421 is about 4592.8663163650. The cubic root of 21094421 is about 276.3052921271.

The spelling of 21094421 in words is "twenty-one million, ninety-four thousand, four hundred twenty-one".