21002021102101 has 4 divisors (see below), whose sum is σ = 22617561186892. Its totient is φ = 19386481017312.

The previous prime is 21002021102089. The next prime is 21002021102137. The reversal of 21002021102101 is 10120112020012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1821352680625 + 19180668421476 = 1349575^2 + 4379574^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002021102101 - 2¹⁵ = 21002021069333 is a prime.

It is a super-2 number, since 2×21002021102101² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1615540084777 = 21002021102101 / (2 + 1 + 0 + 0 + 2 + 0 + 2 + 1 + 1 + 0 + 2 + 1 + 0 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002021102171) 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 3 ways as a sum of consecutive naturals, for example, 807770042376 + ... + 807770042401.

It is an arithmetic number, because the mean of its divisors is an integer number (5654390296723).

Almost surely, 2^{21002021102101} is an apocalyptic number.

It is an amenable number.

21002021102101 is a deficient number, since it is larger than the sum of its proper divisors (1615540084791).

21002021102101 is a wasteful number, since it uses less digits than its factorization.

21002021102101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615540084790.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21002021102101 its reverse (10120112020012), we get a palindrome (31122133122113).

The spelling of 21002021102101 in words is "twenty-one trillion, two billion, twenty-one million, one hundred two thousand, one hundred one".