21243201 has 16 divisors (see below), whose sum is σ = 33060864. Its totient is φ = 11880144.

The previous prime is 21243193. The next prime is 21243227. The reversal of 21243201 is 10234212.

It is not a de Polignac number, because 21243201 - 2³ = 21243193 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21242201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9775 + ... + 11748.

It is an arithmetic number, because the mean of its divisors is an integer number (2066304).

Almost surely, 2^21243201 is an apocalyptic number.

21243201 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21243201 is a deficient number, since it is larger than the sum of its proper divisors (11817663).

21243201 is a wasteful number, since it uses less digits than its factorization.

21243201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21580.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21243201 is about 4609.0347145579. The cubic root of 21243201 is about 276.9533691874.

Adding to 21243201 its reverse (10234212), we get a palindrome (31477413).

The spelling of 21243201 in words is "twenty-one million, two hundred forty-three thousand, two hundred one".