21440097 has 36 divisors (see below), whose sum is σ = 36661716. Its totient is φ = 12035520.

The previous prime is 21440087. The next prime is 21440099. The reversal of 21440097 is 79004412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4498641 + 16941456 = 2121^2 + 4116^2 .

It is not a de Polignac number, because 21440097 - 2⁷ = 21439969 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21440097.

It is not an unprimeable number, because it can be changed into a prime (21440099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 26503 + ... + 27299.

It is an arithmetic number, because the mean of its divisors is an integer number (1018381).

Almost surely, 2^21440097 is an apocalyptic number.

It is an amenable number.

21440097 is a deficient number, since it is larger than the sum of its proper divisors (15221619).

21440097 is a wasteful number, since it uses less digits than its factorization.

21440097 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878 (or 868 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21440097 is about 4630.3452355089. The cubic root of 21440097 is about 277.8064012756.

The spelling of 21440097 in words is "twenty-one million, four hundred forty thousand, ninety-seven".