21030440 has 32 divisors (see below), whose sum is σ = 48422880. Its totient is φ = 8215872.

The previous prime is 21030403. The next prime is 21030463. The reversal of 21030440 is 4403012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4394 + ... + 7833.

It is an arithmetic number, because the mean of its divisors is an integer number (1513215).

Almost surely, 2^21030440 is an apocalyptic number.

21030440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21030440 is an abundant number, since it is smaller than the sum of its proper divisors (27392440).

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

21030440 is a wasteful number, since it uses less digits than its factorization.

21030440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12281 (or 12277 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21030440 is about 4585.8957685495. The cubic root of 21030440 is about 276.0256574901.

Adding to 21030440 its reverse (4403012), we get a palindrome (25433452).

The spelling of 21030440 in words is "twenty-one million, thirty thousand, four hundred forty".