21261071673 has 16 divisors (see below), whose sum is σ = 32031748800. Its totient is φ = 13933808640.

The previous prime is 21261071659. The next prime is 21261071681. The reversal of 21261071673 is 37617016212.

It is a happy number.

21261071673 is a `hidden beast` number, since 21 + 2 + 610 + 7 + 16 + 7 + 3 = 666.

It is not a de Polignac number, because 21261071673 - 2⁸ = 21261071417 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21261071633) 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, 6671688 + ... + 6674873.

It is an arithmetic number, because the mean of its divisors is an integer number (2001984300).

Almost surely, 2^21261071673 is an apocalyptic number.

It is an amenable number.

21261071673 is a deficient number, since it is larger than the sum of its proper divisors (10770677127).

21261071673 is a wasteful number, since it uses less digits than its factorization.

21261071673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13346629 (or 13346623 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

Adding to 21261071673 its reverse (37617016212), we get a palindrome (58878087885).

The spelling of 21261071673 in words is "twenty-one billion, two hundred sixty-one million, seventy-one thousand, six hundred seventy-three".