221000001021 has 32 divisors (see below), whose sum is σ = 338012697600. Its totient is φ = 142562185920.

The previous prime is 221000000987. The next prime is 221000001059. The reversal of 221000001021 is 120100000122.

It is not a de Polignac number, because 221000001021 - 2¹⁵ = 220999968253 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 221000000994 and 221000001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221000002021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9856195 + ... + 9878591.

It is an arithmetic number, because the mean of its divisors is an integer number (10562896800).

Almost surely, 2^221000001021 is an apocalyptic number.

It is an amenable number.

221000001021 is a deficient number, since it is larger than the sum of its proper divisors (117012696579).

221000001021 is a wasteful number, since it uses less digits than its factorization.

221000001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34226 (or 34220 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 221000001021 its reverse (120100000122), we get a palindrome (341100001143).

The spelling of 221000001021 in words is "two hundred twenty-one billion, one thousand, twenty-one".