221012020021 has 8 divisors (see below), whose sum is σ = 238082002200. Its totient is φ = 203951903232.

The previous prime is 221012020007. The next prime is 221012020027. The reversal of 221012020021 is 120020210122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 26663297521 + 194348722500 = 163289^2 + 440850^2 .

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 221012020021 - 2²⁷ = 220877802293 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221012019983 and 221012020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221012020027) 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 7 ways as a sum of consecutive naturals, for example, 2419780 + ... + 2509453.

It is an arithmetic number, because the mean of its divisors is an integer number (29760250275).

Almost surely, 2^221012020021 is an apocalyptic number.

It is an amenable number.

221012020021 is a deficient number, since it is larger than the sum of its proper divisors (17069982179).

221012020021 is a wasteful number, since it uses less digits than its factorization.

221012020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4932695.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 221012020021 its reverse (120020210122), we get a palindrome (341032230143).

The spelling of 221012020021 in words is "two hundred twenty-one billion, twelve million, twenty thousand, twenty-one".