21144023 has 4 divisors (see below), whose sum is σ = 21203280. Its totient is φ = 21084768.

The previous prime is 21143999. The next prime is 21144029. The reversal of 21144023 is 32044112.

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 21144023 - 2²⁰ = 20095447 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21143992 and 21144010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144029) 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, 29090 + ... + 29807.

It is an arithmetic number, because the mean of its divisors is an integer number (5300820).

Almost surely, 2^21144023 is an apocalyptic number.

21144023 is a deficient number, since it is larger than the sum of its proper divisors (59257).

21144023 is an equidigital number, since it uses as much as digits as its factorization.

21144023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59256.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21144023 is about 4598.2630416278. The cubic root of 21144023 is about 276.5216932121.

Adding to 21144023 its reverse (32044112), we get a palindrome (53188135).

The spelling of 21144023 in words is "twenty-one million, one hundred forty-four thousand, twenty-three".