21111445 has 4 divisors (see below), whose sum is σ = 25333740. Its totient is φ = 16889152.

The previous prime is 21111397. The next prime is 21111457. The reversal of 21111445 is 54411112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10909809 + 10201636 = 3303^2 + 3194^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111445 - 2¹¹ = 21109397 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2111140 + ... + 2111149.

It is an arithmetic number, because the mean of its divisors is an integer number (6333435).

Almost surely, 2^21111445 is an apocalyptic number.

It is an amenable number.

21111445 is a deficient number, since it is larger than the sum of its proper divisors (4222295).

21111445 is an equidigital number, since it uses as much as digits as its factorization.

21111445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4222294.

The product of its digits is 160, while the sum is 19.

The square root of 21111445 is about 4594.7192514886. The cubic root of 21111445 is about 276.3796017668.

Adding to 21111445 its reverse (54411112), we get a palindrome (75522557).

The spelling of 21111445 in words is "twenty-one million, one hundred eleven thousand, four hundred forty-five".