21440109 has 4 divisors (see below), whose sum is σ = 28586816. Its totient is φ = 14293404.

The previous prime is 21440099. The next prime is 21440119. The reversal of 21440109 is 90104412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21440099) and next prime (21440119).

It is not a de Polignac number, because 21440109 - 2⁷ = 21439981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3573349 + ... + 3573354.

It is an arithmetic number, because the mean of its divisors is an integer number (7146704).

Almost surely, 2^21440109 is an apocalyptic number.

It is an amenable number.

21440109 is a deficient number, since it is larger than the sum of its proper divisors (7146707).

21440109 is an equidigital number, since it uses as much as digits as its factorization.

21440109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7146706.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21440109 is about 4630.3465313084. The cubic root of 21440109 is about 277.8064531049.

The spelling of 21440109 in words is "twenty-one million, four hundred forty thousand, one hundred nine".