21202420173 has 24 divisors (see below), whose sum is σ = 32145036000. Its totient is φ = 12406843680.

The previous prime is 21202420157. The next prime is 21202420243. The reversal of 21202420173 is 37102420212.

It is not a de Polignac number, because 21202420173 - 2⁴ = 21202420157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202420123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 996523 + ... + 1017576.

It is an arithmetic number, because the mean of its divisors is an integer number (1339376500).

Almost surely, 2^21202420173 is an apocalyptic number.

It is an amenable number.

21202420173 is a deficient number, since it is larger than the sum of its proper divisors (10942615827).

21202420173 is a wasteful number, since it uses less digits than its factorization.

21202420173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014153 (or 2014142 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

Adding to 21202420173 its reverse (37102420212), we get a palindrome (58304840385).

The spelling of 21202420173 in words is "twenty-one billion, two hundred two million, four hundred twenty thousand, one hundred seventy-three".