21001112121021 has 8 divisors (see below), whose sum is σ = 28002156446880. Its totient is φ = 14000404604592.

The previous prime is 21001112120951. The next prime is 21001112121023. The reversal of 21001112121021 is 12012121110012.

It is a happy number.

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

It is not a de Polignac number, because 21001112121021 - 2²¹ = 21001110023869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001112121023) 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, 84056830 + ... + 84306303.

It is an arithmetic number, because the mean of its divisors is an integer number (3500269555860).

Almost surely, 2^{21001112121021} is an apocalyptic number.

It is an amenable number.

21001112121021 is a deficient number, since it is larger than the sum of its proper divisors (7001044325859).

21001112121021 is a wasteful number, since it uses less digits than its factorization.

21001112121021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168404715.

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

Adding to 21001112121021 its reverse (12012121110012), we get a palindrome (33013233231033).

The spelling of 21001112121021 in words is "twenty-one trillion, one billion, one hundred twelve million, one hundred twenty-one thousand, twenty-one".