21440919 has 4 divisors (see below), whose sum is σ = 28587896. Its totient is φ = 14293944.

The previous prime is 21440917. The next prime is 21440941. The reversal of 21440919 is 91904412.

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

It is not a de Polignac number, because 21440919 - 2¹ = 21440917 is a prime.

It is a super-2 number, since 2×21440919² = 919426015129122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440917) 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, 3573484 + ... + 3573489.

It is an arithmetic number, because the mean of its divisors is an integer number (7146974).

Almost surely, 2^21440919 is an apocalyptic number.

21440919 is a deficient number, since it is larger than the sum of its proper divisors (7146977).

21440919 is an equidigital number, since it uses as much as digits as its factorization.

21440919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7146976.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21440919 is about 4630.4339969381. The cubic root of 21440919 is about 277.8099515385.

The spelling of 21440919 in words is "twenty-one million, four hundred forty thousand, nine hundred nineteen".