21012221001 has 16 divisors (see below), whose sum is σ = 28513425600. Its totient is φ = 13759953408.

The previous prime is 21012220969. The next prime is 21012221047. The reversal of 21012221001 is 10012221012.

It is not a de Polignac number, because 21012221001 - 2⁵ = 21012220969 is a prime.

It is a super-3 number, since 3×21012221001³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21012241001) 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, 183805 + ... + 275333.

It is an arithmetic number, because the mean of its divisors is an integer number (1782089100).

Almost surely, 2^21012221001 is an apocalyptic number.

It is an amenable number.

21012221001 is a deficient number, since it is larger than the sum of its proper divisors (7501204599).

21012221001 is a wasteful number, since it uses less digits than its factorization.

21012221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92888.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21012221001 its reverse (10012221012), we get a palindrome (31024442013).

The spelling of 21012221001 in words is "twenty-one billion, twelve million, two hundred twenty-one thousand, one".