21030744 has 32 divisors (see below), whose sum is σ = 60088320. Its totient is φ = 6008736.

The previous prime is 21030721. The next prime is 21030767. The reversal of 21030744 is 44703012.

It is an interprime number because it is at equal distance from previous prime (21030721) and next prime (21030767).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21030744.

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, 62424 + ... + 62759.

It is an arithmetic number, because the mean of its divisors is an integer number (1877760).

Almost surely, 2^21030744 is an apocalyptic number.

21030744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21030744 is an abundant number, since it is smaller than the sum of its proper divisors (39057576).

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

21030744 is a wasteful number, since it uses less digits than its factorization.

21030744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125199 (or 125195 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21030744 is about 4585.9289135354. The cubic root of 21030744 is about 276.0269874892.

Adding to 21030744 its reverse (44703012), we get a palindrome (65733756).

The spelling of 21030744 in words is "twenty-one million, thirty thousand, seven hundred forty-four".