21021093 has 8 divisors (see below), whose sum is σ = 31142400. Its totient is φ = 14014044.

The previous prime is 21021083. The next prime is 21021101. The reversal of 21021093 is 39012012.

It is a happy number.

It is not a de Polignac number, because 21021093 - 2⁸ = 21020837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389253 + ... + 389306.

It is an arithmetic number, because the mean of its divisors is an integer number (3892800).

Almost surely, 2^21021093 is an apocalyptic number.

It is an amenable number.

21021093 is a deficient number, since it is larger than the sum of its proper divisors (10121307).

21021093 is an equidigital number, since it uses as much as digits as its factorization.

21021093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778568 (or 778562 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 21021093 is about 4584.8765523185. The cubic root of 21021093 is about 275.9847581375.

The spelling of 21021093 in words is "twenty-one million, twenty-one thousand, ninety-three".