21010121121001 has 8 divisors (see below), whose sum is σ = 21531884358600. Its totient is φ = 20488801752960.

The previous prime is 21010121120971. The next prime is 21010121121151. The reversal of 21010121121001 is 10012112101012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5486481720976 + 15523639400025 = 2342324^2 + 3940005^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21010121121001 - 2⁹ = 21010121120489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21010121121401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110871546 + ... + 111060883.

It is an arithmetic number, because the mean of its divisors is an integer number (2691485544825).

Almost surely, 2^{21010121121001} is an apocalyptic number.

It is an amenable number.

21010121121001 is a deficient number, since it is larger than the sum of its proper divisors (521763237599).

21010121121001 is a wasteful number, since it uses less digits than its factorization.

21010121121001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221934779.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21010121121001 its reverse (10012112101012), we get a palindrome (31022233222013).

The spelling of 21010121121001 in words is "twenty-one trillion, ten billion, one hundred twenty-one million, one hundred twenty-one thousand, one".