210043021 has 4 divisors (see below), whose sum is σ = 210073500. Its totient is φ = 210012544.

The previous prime is 210043019. The next prime is 210043049. The reversal of 210043021 is 120340012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 92428996 + 117614025 = 9614^2 + 10845^2 .

It is a cyclic number.

It is not a de Polignac number, because 210043021 - 2¹ = 210043019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 210042992 and 210043010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210043051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555 + ... + 20503.

It is an arithmetic number, because the mean of its divisors is an integer number (52518375).

Almost surely, 2^210043021 is an apocalyptic number.

It is an amenable number.

210043021 is a deficient number, since it is larger than the sum of its proper divisors (30479).

210043021 is a wasteful number, since it uses less digits than its factorization.

210043021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30478.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 210043021 is about 14492.8610356962. The cubic root of 210043021 is about 594.4327819440.

Adding to 210043021 its reverse (120340012), we get a palindrome (330383033).

It can be divided in two parts, 21004 and 3021, that added together give a square (24025 = 155²).

The spelling of 210043021 in words is "two hundred ten million, forty-three thousand, twenty-one".