21000211220121 has 16 divisors (see below), whose sum is σ = 33032590307328. Its totient is φ = 11613020029200.

The previous prime is 21000211220081. The next prime is 21000211220159. The reversal of 21000211220121 is 12102211200012.

It is not a de Polignac number, because 21000211220121 - 2⁶ = 21000211220057 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000211220121.

It is not an unprimeable number, because it can be changed into a prime (21000211220161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16129193835 + ... + 16129195136.

It is an arithmetic number, because the mean of its divisors is an integer number (2064536894208).

Almost surely, 2^{21000211220121} is an apocalyptic number.

21000211220121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21000211220121 is a deficient number, since it is larger than the sum of its proper divisors (12032379087207).

21000211220121 is a wasteful number, since it uses less digits than its factorization.

21000211220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32258389012.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21000211220121 its reverse (12102211200012), we get a palindrome (33102422420133).

The spelling of 21000211220121 in words is "twenty-one trillion, two hundred eleven million, two hundred twenty thousand, one hundred twenty-one".