21002041 has 4 divisors (see below), whose sum is σ = 21210084. Its totient is φ = 20794000.

The previous prime is 21002039. The next prime is 21002077. The reversal of 21002041 is 14020012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19053225 + 1948816 = 4365^2 + 1396^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002041 - 2¹ = 21002039 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002081) 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, 103870 + ... + 104071.

It is an arithmetic number, because the mean of its divisors is an integer number (5302521).

Almost surely, 2^21002041 is an apocalyptic number.

It is an amenable number.

21002041 is a deficient number, since it is larger than the sum of its proper divisors (208043).

21002041 is a wasteful number, since it uses less digits than its factorization.

21002041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208042.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21002041 is about 4582.7983809022. The cubic root of 21002041 is about 275.9013553870.

Adding to 21002041 its reverse (14020012), we get a palindrome (35022053).

The spelling of 21002041 in words is "twenty-one million, two thousand, forty-one".