21649366373 has 4 divisors (see below), whose sum is σ = 21703899180. Its totient is φ = 21594833568.

The previous prime is 21649366339. The next prime is 21649366381. The reversal of 21649366373 is 37366394612.

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 10064503684 + 11584862689 = 100322^2 + 107633^2 .

It is a cyclic number.

It is not a de Polignac number, because 21649366373 - 2¹⁰ = 21649365349 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 (21649366313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27265808 + ... + 27266601.

It is an arithmetic number, because the mean of its divisors is an integer number (5425974795).

Almost surely, 2^21649366373 is an apocalyptic number.

It is an amenable number.

21649366373 is a deficient number, since it is larger than the sum of its proper divisors (54532807).

21649366373 is an equidigital number, since it uses as much as digits as its factorization.

21649366373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54532806.

The product of its digits is 2939328, while the sum is 50.

The spelling of 21649366373 in words is "twenty-one billion, six hundred forty-nine million, three hundred sixty-six thousand, three hundred seventy-three".