21121101001 has 24 divisors (see below), whose sum is σ = 28514234304. Its totient is φ = 15191991360.

The previous prime is 21121100963. The next prime is 21121101059. The reversal of 21121101001 is 10010112112.

It is not a de Polignac number, because 21121101001 - 2¹⁷ = 21120969929 is a prime.

It is a super-2 number, since 2×21121101001² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121101601) 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 23 ways as a sum of consecutive naturals, for example, 798526 + ... + 824551.

It is an arithmetic number, because the mean of its divisors is an integer number (1188093096).

Almost surely, 2^21121101001 is an apocalyptic number.

It is an amenable number.

21121101001 is a deficient number, since it is larger than the sum of its proper divisors (7393133303).

21121101001 is a wasteful number, since it uses less digits than its factorization.

21121101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623121 (or 1623108 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21121101001 its reverse (10010112112), we get a palindrome (31131213113).

The spelling of 21121101001 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, one".