21270943 has 4 divisors (see below), whose sum is σ = 21299800. Its totient is φ = 21242088.

The previous prime is 21270941. The next prime is 21270947. The reversal of 21270943 is 34907212.

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 21270943 - 2¹ = 21270941 is a prime.

It is a super-2 number, since 2×21270943² = 904906032218498, which contains 22 as substring.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21270941) 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, 13293 + ... + 14806.

It is an arithmetic number, because the mean of its divisors is an integer number (5324950).

Almost surely, 2^21270943 is an apocalyptic number.

21270943 is a deficient number, since it is larger than the sum of its proper divisors (28857).

21270943 is an equidigital number, since it uses as much as digits as its factorization.

21270943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28856.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21270943 is about 4612.0432565187. The cubic root of 21270943 is about 277.0738767358.

The spelling of 21270943 in words is "twenty-one million, two hundred seventy thousand, nine hundred forty-three".