21020093 has 2 divisors, whose sum is σ = 21020094. Its totient is φ = 21020092.

The previous prime is 21020089. The next prime is 21020117. The reversal of 21020093 is 39002012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16345849 + 4674244 = 4043^2 + 2162^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020093 - 2² = 21020089 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510046 + 10510047.

It is an arithmetic number, because the mean of its divisors is an integer number (10510047).

Almost surely, 2^21020093 is an apocalyptic number.

It is an amenable number.

21020093 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020093 is an equidigital number, since it uses as much as digits as its factorization.

21020093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21020093 is about 4584.7674968312. The cubic root of 21020093 is about 275.9803817534.

It can be divided in two parts, 2102009 and 3, that added together give a palindrome (2102012).

The spelling of 21020093 in words is "twenty-one million, twenty thousand, ninety-three".