21030402221 has 8 divisors (see below), whose sum is σ = 21127686840.
Its totient is φ = 20933178112.
The previous prime is 21030402193. The next prime is 21030402229. The reversal of 21030402221 is 12220403012.
It can be written as a sum of positive squares in 4 ways, for example, as 12577622500 + 8452779721 = 112150^2 + 91939^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-21030402221 is a prime.
It is a Duffinian number.
It is a self number, because there is not a number n which added to its sum of digits gives 21030402221.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21030402229) 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, 776321 + ... + 802953.
It is an arithmetic number, because the mean of its divisors is an integer number (2640960855).
Almost surely, 221030402221 is an apocalyptic number.
It is an amenable number.
21030402221 is a deficient number, since it is larger than the sum of its proper divisors (97284619).
21030402221 is a wasteful number, since it uses less digits than its factorization.
21030402221 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 30255.
The product of its (nonzero) digits is 192, while the sum is 17.
Adding to 21030402221 its reverse (12220403012), we get a palindrome (33250805233).
The spelling of 21030402221 in words is "twenty-one billion, thirty million, four hundred two thousand, two hundred twenty-one".