21195397173 has 16 divisors (see below), whose sum is σ = 30283436736. Its totient is φ = 13138840320.

The previous prime is 21195397169. The next prime is 21195397229. The reversal of 21195397173 is 37179359112.

It is a happy number.

It is not a de Polignac number, because 21195397173 - 2² = 21195397169 is a prime.

It is a super-2 number, since 2×21195397173² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21195397103) 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 15 ways as a sum of consecutive naturals, for example, 2499358 + ... + 2507823.

It is an arithmetic number, because the mean of its divisors is an integer number (1892714796).

Almost surely, 2^21195397173 is an apocalyptic number.

It is an amenable number.

21195397173 is a deficient number, since it is larger than the sum of its proper divisors (9088039563).

21195397173 is a wasteful number, since it uses less digits than its factorization.

21195397173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5007284.

The product of its digits is 357210, while the sum is 48.

The spelling of 21195397173 in words is "twenty-one billion, one hundred ninety-five million, three hundred ninety-seven thousand, one hundred seventy-three".