21041023 has 4 divisors (see below), whose sum is σ = 21062808. Its totient is φ = 21019240.

The previous prime is 21041011. The next prime is 21041029. The reversal of 21041023 is 32014012.

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

It is a cyclic number.

It is not a de Polignac number, because 21041023 - 2⁹ = 21040511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21040994 and 21041012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21041029) 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, 9373 + ... + 11398.

It is an arithmetic number, because the mean of its divisors is an integer number (5265702).

Almost surely, 2^21041023 is an apocalyptic number.

21041023 is a deficient number, since it is larger than the sum of its proper divisors (21785).

21041023 is a wasteful number, since it uses less digits than its factorization.

21041023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21784.

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

The square root of 21041023 is about 4587.0494874156. The cubic root of 21041023 is about 276.0719505407.

Adding to 21041023 its reverse (32014012), we get a palindrome (53055035).

The spelling of 21041023 in words is "twenty-one million, forty-one thousand, twenty-three".