21014321 has 4 divisors (see below), whose sum is σ = 21040500. Its totient is φ = 20988144.

The previous prime is 21014303. The next prime is 21014327. The reversal of 21014321 is 12341012.

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 9991921 + 11022400 = 3161^2 + 3320^2 .

It is a cyclic number.

It is not a de Polignac number, because 21014321 - 2¹⁴ = 20997937 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21014296 and 21014305.

It is not an unprimeable number, because it can be changed into a prime (21014327) 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, 11846 + ... + 13503.

It is an arithmetic number, because the mean of its divisors is an integer number (5260125).

Almost surely, 2^21014321 is an apocalyptic number.

It is an amenable number.

21014321 is a deficient number, since it is larger than the sum of its proper divisors (26179).

21014321 is an equidigital number, since it uses as much as digits as its factorization.

21014321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26178.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21014321 is about 4584.1379778536. The cubic root of 21014321 is about 275.9551185510.

Adding to 21014321 its reverse (12341012), we get a palindrome (33355333).

The spelling of 21014321 in words is "twenty-one million, fourteen thousand, three hundred twenty-one".