21227643 has 16 divisors (see below), whose sum is σ = 32816640. Its totient is φ = 13536072.

The previous prime is 21227629. The next prime is 21227671. The reversal of 21227643 is 34672212.

21227643 is a `hidden beast` number, since 2 + 12 + 2 + 7 + 643 = 666.

It is not a de Polignac number, because 21227643 - 2⁸ = 21227387 is a prime.

It is a super-2 number, since 2×21227643² = 901225654670898, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21227243) 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, 16471 + ... + 17712.

It is an arithmetic number, because the mean of its divisors is an integer number (2051040).

Almost surely, 2^21227643 is an apocalyptic number.

21227643 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21227643 is a deficient number, since it is larger than the sum of its proper divisors (11588997).

21227643 is a wasteful number, since it uses less digits than its factorization.

21227643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34215 (or 34209 counting only the distinct ones).

The product of its digits is 4032, while the sum is 27.

The square root of 21227643 is about 4607.3466333672. The cubic root of 21227643 is about 276.8857413875.

Adding to 21227643 its reverse (34672212), we get a palindrome (55899855).

The spelling of 21227643 in words is "twenty-one million, two hundred twenty-seven thousand, six hundred forty-three".