21648023 has 4 divisors (see below), whose sum is σ = 21675528. Its totient is φ = 21620520.

The previous prime is 21648001. The next prime is 21648047. The reversal of 21648023 is 32084612.

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 21648023 - 2¹⁴ = 21631639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21647983 and 21648001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21645023) 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, 12536 + ... + 14157.

It is an arithmetic number, because the mean of its divisors is an integer number (5418882).

Almost surely, 2^21648023 is an apocalyptic number.

21648023 is a deficient number, since it is larger than the sum of its proper divisors (27505).

21648023 is an equidigital number, since it uses as much as digits as its factorization.

21648023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27504.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21648023 is about 4652.7435992111. The cubic root of 21648023 is about 278.7015689351.

The spelling of 21648023 in words is "twenty-one million, six hundred forty-eight thousand, twenty-three".