21010012221 has 8 divisors (see below), whose sum is σ = 30560017824. Its totient is φ = 12733340720.

The previous prime is 21010012201. The next prime is 21010012271. The reversal of 21010012221 is 12221001012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21010012221 - 2⁵ = 21010012189 is a prime.

It is a super-2 number, since 2×21010012221² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21010012197 and 21010012206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010012201) 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 7 ways as a sum of consecutive naturals, for example, 318333486 + ... + 318333551.

It is an arithmetic number, because the mean of its divisors is an integer number (3820002228).

Almost surely, 2^21010012221 is an apocalyptic number.

It is an amenable number.

21010012221 is a deficient number, since it is larger than the sum of its proper divisors (9550005603).

21010012221 is a wasteful number, since it uses less digits than its factorization.

21010012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636667051.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21010012221 its reverse (12221001012), we get a palindrome (33231013233).

The spelling of 21010012221 in words is "twenty-one billion, ten million, twelve thousand, two hundred twenty-one".