21005030 has 32 divisors (see below), whose sum is σ = 40339296. Its totient is φ = 7847424.

The previous prime is 21005029. The next prime is 21005041. The reversal of 21005030 is 3050012.

It is a super-2 number, since 2×21005030² = 882422570601800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26297 + ... + 27083.

It is an arithmetic number, because the mean of its divisors is an integer number (1260603).

Almost surely, 2^21005030 is an apocalyptic number.

21005030 is a deficient number, since it is larger than the sum of its proper divisors (19334266).

21005030 is a wasteful number, since it uses less digits than its factorization.

21005030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968.

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 21005030 is about 4583.1244800900. The cubic root of 21005030 is about 275.9144434806.

Adding to 21005030 its reverse (3050012), we get a palindrome (24055042).

The spelling of 21005030 in words is "twenty-one million, five thousand, thirty".