21227745 has 32 divisors (see below), whose sum is σ = 42347520. Its totient is φ = 8821440.

The previous prime is 21227711. The next prime is 21227753. The reversal of 21227745 is 54772212.

It is not a de Polignac number, because 21227745 - 2¹⁵ = 21194977 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8035 + ... + 10344.

It is an arithmetic number, because the mean of its divisors is an integer number (1323360).

Almost surely, 2^21227745 is an apocalyptic number.

It is an amenable number.

21227745 is a deficient number, since it is larger than the sum of its proper divisors (21119775).

21227745 is a wasteful number, since it uses less digits than its factorization.

21227745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18405.

The product of its digits is 7840, while the sum is 30.

The square root of 21227745 is about 4607.3577026317. The cubic root of 21227745 is about 276.8861848705.

Adding to 21227745 its reverse (54772212), we get a palindrome (75999957).

The spelling of 21227745 in words is "twenty-one million, two hundred twenty-seven thousand, seven hundred forty-five".