21030310 has 48 divisors (see below), whose sum is σ = 44470944. Its totient is φ = 7139328.

The previous prime is 21030301. The next prime is 21030313. The reversal of 21030310 is 1303012.

It is a super-2 number, since 2×21030310² = 884547877392200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030313) 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, 81702 + ... + 81958.

It is an arithmetic number, because the mean of its divisors is an integer number (926478).

Almost surely, 2^21030310 is an apocalyptic number.

21030310 is an abundant number, since it is smaller than the sum of its proper divisors (23440634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21030310 is a wasteful number, since it uses less digits than its factorization.

21030310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21030310 is about 4585.8815946337. The cubic root of 21030310 is about 276.0250887366.

Adding to 21030310 its reverse (1303012), we get a palindrome (22333322).

The spelling of 21030310 in words is "twenty-one million, thirty thousand, three hundred ten".