21003043 has 8 divisors (see below), whose sum is σ = 21255680. Its totient is φ = 20752200.

The previous prime is 21003011. The next prime is 21003053. The reversal of 21003043 is 34030012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21003043 - 2⁵ = 21003011 is a prime.

It is a super-2 number, since 2×21003043² = 882255630519698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003053) 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 7 ways as a sum of consecutive naturals, for example, 55228 + ... + 55606.

It is an arithmetic number, because the mean of its divisors is an integer number (2656960).

Almost surely, 2^21003043 is an apocalyptic number.

21003043 is a deficient number, since it is larger than the sum of its proper divisors (252637).

21003043 is a wasteful number, since it uses less digits than its factorization.

21003043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21003043 is about 4582.9077014489. The cubic root of 21003043 is about 275.9057430362.

Adding to 21003043 its reverse (34030012), we get a palindrome (55033055).

The spelling of 21003043 in words is "twenty-one million, three thousand, forty-three".