21302073 has 24 divisors (see below), whose sum is σ = 33496008. Its totient is φ = 12966912.

The previous prime is 21302063. The next prime is 21302081. The reversal of 21302073 is 37020312.

It can be written as a sum of positive squares in 4 ways, for example, as 1159929 + 20142144 = 1077^2 + 4488^2 .

It is not a de Polignac number, because 21302073 - 2²⁴ = 4524857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21302063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10411 + ... + 12287.

It is an arithmetic number, because the mean of its divisors is an integer number (1395667).

Almost surely, 2^21302073 is an apocalyptic number.

It is an amenable number.

21302073 is a deficient number, since it is larger than the sum of its proper divisors (12193935).

21302073 is a wasteful number, since it uses less digits than its factorization.

21302073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1993 (or 1990 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 18.

The square root of 21302073 is about 4615.4168825795. The cubic root of 21302073 is about 277.2089766150.

Adding to 21302073 its reverse (37020312), we get a palindrome (58322385).

The spelling of 21302073 in words is "twenty-one million, three hundred two thousand, seventy-three".