21001121001001 has 16 divisors (see below), whose sum is σ = 21187184914368. Its totient is φ = 20815455731200.

The previous prime is 21001121000987. The next prime is 21001121001019. The reversal of 21001121001001 is 10010012110012.

It is a cyclic number.

It is not a de Polignac number, because 21001121001001 - 2¹³ = 21001120992809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001121001061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 834590646 + ... + 834615808.

It is an arithmetic number, because the mean of its divisors is an integer number (1324199057148).

Almost surely, 2^{21001121001001} is an apocalyptic number.

It is an amenable number.

21001121001001 is a deficient number, since it is larger than the sum of its proper divisors (186063913367).

21001121001001 is a wasteful number, since it uses less digits than its factorization.

21001121001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32792.

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

Adding to 21001121001001 its reverse (10010012110012), we get a palindrome (31011133111013).

The spelling of 21001121001001 in words is "twenty-one trillion, one billion, one hundred twenty-one million, one thousand, one".