21473735221 has 4 divisors (see below), whose sum is σ = 21474036000. Its totient is φ = 21473434444.

The previous prime is 21473735189. The next prime is 21473735273. The reversal of 21473735221 is 12253737412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21473735221 - 2⁵ = 21473735189 is a prime.

It is a super-2 number, since 2×21473735221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21473735021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24480 + ... + 208678.

It is an arithmetic number, because the mean of its divisors is an integer number (5368509000).

Almost surely, 2^21473735221 is an apocalyptic number.

It is an amenable number.

21473735221 is a deficient number, since it is larger than the sum of its proper divisors (300779).

21473735221 is a wasteful number, since it uses less digits than its factorization.

21473735221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300778.

The product of its digits is 70560, while the sum is 37.

It can be divided in two parts, 21473735 and 221, that added together give a square (21473956 = 4634²).

The spelling of 21473735221 in words is "twenty-one billion, four hundred seventy-three million, seven hundred thirty-five thousand, two hundred twenty-one".