21121110221001 has 16 divisors (see below), whose sum is σ = 32712164466048. Its totient is φ = 11871350006400.

The previous prime is 21121110220949. The next prime is 21121110221033. The reversal of 21121110221001 is 10012201112112.

It is a happy number.

It is not a de Polignac number, because 21121110221001 - 2³⁷ = 20983671267529 is a prime.

It is a super-2 number, since 2×21121110221001² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21121110221201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8243991780 + ... + 8243994341.

It is an arithmetic number, because the mean of its divisors is an integer number (2044510279128).

Almost surely, 2^{21121110221001} is an apocalyptic number.

21121110221001 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21121110221001 is a deficient number, since it is larger than the sum of its proper divisors (11591054245047).

21121110221001 is a wasteful number, since it uses less digits than its factorization.

21121110221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16487986192.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21121110221001 its reverse (10012201112112), we get a palindrome (31133311333113).

The spelling of 21121110221001 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, two hundred twenty-one thousand, one".