21021230 has 32 divisors (see below), whose sum is σ = 39463200. Its totient is φ = 8052352.

The previous prime is 21021229. The next prime is 21021251. The reversal of 21021230 is 3212012.

It is a happy number.

It is a super-2 number, since 2×21021230² = 883784221425800, 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, 49961 + ... + 50379.

It is an arithmetic number, because the mean of its divisors is an integer number (1233225).

Almost surely, 2^21021230 is an apocalyptic number.

21021230 is a deficient number, since it is larger than the sum of its proper divisors (18441970).

21021230 is a wasteful number, since it uses less digits than its factorization.

21021230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628.

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21021230 is about 4584.8914927182. The cubic root of 21021230 is about 275.9853576913.

Adding to 21021230 its reverse (3212012), we get a palindrome (24233242).

The spelling of 21021230 in words is "twenty-one million, twenty-one thousand, two hundred thirty".