21264443 has 8 divisors (see below), whose sum is σ = 22249728. Its totient is φ = 20284264.

The previous prime is 21264427. The next prime is 21264449. The reversal of 21264443 is 34446212.

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 21264443 - 2⁴ = 21264427 is a prime.

It is a super-2 number, since 2×21264443² = 904353072200498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21264449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9146 + ... + 11232.

It is an arithmetic number, because the mean of its divisors is an integer number (2781216).

Almost surely, 2^21264443 is an apocalyptic number.

21264443 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21264443 is a deficient number, since it is larger than the sum of its proper divisors (985285).

21264443 is a wasteful number, since it uses less digits than its factorization.

21264443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2553.

The product of its digits is 4608, while the sum is 26.

The square root of 21264443 is about 4611.3385258513. The cubic root of 21264443 is about 277.0456510059.

The spelling of 21264443 in words is "twenty-one million, two hundred sixty-four thousand, four hundred forty-three".