221221200000021 has 32 divisors (see below), whose sum is σ = 319368118108032. Its totient is φ = 135400510586880.

The previous prime is 221221199999881. The next prime is 221221200000071. The reversal of 221221200000021 is 120000002122122.

It is not a de Polignac number, because 221221200000021 - 2²¹ = 221221197902869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221221200000071) 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, 30449046 + ... + 37007928.

It is an arithmetic number, because the mean of its divisors is an integer number (9980253690876).

Almost surely, 2^{221221200000021} is an apocalyptic number.

It is an amenable number.

221221200000021 is a deficient number, since it is larger than the sum of its proper divisors (98146918108011).

221221200000021 is a wasteful number, since it uses less digits than its factorization.

221221200000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6563573.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 221221200000021 its reverse (120000002122122), we get a palindrome (341221202122143).

It can be divided in two parts, 22122 and 1200000021, that multiplied together give a palindrome (26546400464562).

The spelling of 221221200000021 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred million, twenty-one", and thus it is an aban number.