21460021 has 8 divisors (see below), whose sum is σ = 23498784. Its totient is φ = 19435920.

The previous prime is 21460007. The next prime is 21460057. The reversal of 21460021 is 12006412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21460021 - 2²³ = 13071413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21459977 and 21460004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21463021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 475 + ... + 6568.

It is an arithmetic number, because the mean of its divisors is an integer number (2937348).

Almost surely, 2^21460021 is an apocalyptic number.

It is an amenable number.

21460021 is a deficient number, since it is larger than the sum of its proper divisors (2038763).

21460021 is a wasteful number, since it uses less digits than its factorization.

21460021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7331.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21460021 is about 4632.4961953573. The cubic root of 21460021 is about 277.8924285774.

Adding to 21460021 its reverse (12006412), we get a palindrome (33466433).

The spelling of 21460021 in words is "twenty-one million, four hundred sixty thousand, twenty-one".