21002830 has 16 divisors (see below), whose sum is σ = 38324304. Its totient is φ = 8285760.

The previous prime is 21002797. The next prime is 21002857. The reversal of 21002830 is 3820012.

It is a happy number.

It is a super-2 number, since 2×21002830² = 882237736017800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 13656 + ... + 15115.

It is an arithmetic number, because the mean of its divisors is an integer number (2395269).

Almost surely, 2^21002830 is an apocalyptic number.

21002830 is a deficient number, since it is larger than the sum of its proper divisors (17321474).

21002830 is a wasteful number, since it uses less digits than its factorization.

21002830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28851.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21002830 is about 4582.8844628683. The cubic root of 21002830 is about 275.9048103440.

Adding to 21002830 its reverse (3820012), we get a palindrome (24822842).

The spelling of 21002830 in words is "twenty-one million, two thousand, eight hundred thirty".