21440775653 has 6 divisors (see below), whose sum is σ = 23567133702. Its totient is φ = 19491614120.

The previous prime is 21440775641. The next prime is 21440775673. The reversal of 21440775653 is 35657704412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21329726209 + 111049444 = 146047^2 + 10538^2 .

It is not a de Polignac number, because 21440775653 - 2⁴ = 21440775637 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 (21440775673) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 88598126 + ... + 88598367.

It is an arithmetic number, because the mean of its divisors is an integer number (3927855617).

Almost surely, 2^21440775653 is an apocalyptic number.

It is an amenable number.

21440775653 is a deficient number, since it is larger than the sum of its proper divisors (2126358049).

21440775653 is a wasteful number, since it uses less digits than its factorization.

21440775653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177196515 (or 177196504 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 44.

The spelling of 21440775653 in words is "twenty-one billion, four hundred forty million, seven hundred seventy-five thousand, six hundred fifty-three".