21011002101 has 16 divisors (see below), whose sum is σ = 31285425600. Its totient is φ = 13936227984.

The previous prime is 21011002087. The next prime is 21011002141. The reversal of 21011002101 is 10120011012.

It is a happy number.

It is not a de Polignac number, because 21011002101 - 2¹³ = 21010993909 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011002141) 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 15 ways as a sum of consecutive naturals, for example, 1969771 + ... + 1980408.

It is an arithmetic number, because the mean of its divisors is an integer number (1955339100).

Almost surely, 2^21011002101 is an apocalyptic number.

It is an amenable number.

21011002101 is a deficient number, since it is larger than the sum of its proper divisors (10274423499).

21011002101 is a wasteful number, since it uses less digits than its factorization.

21011002101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3950385 (or 3950379 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21011002101 its reverse (10120011012), we get a palindrome (31131013113).

The spelling of 21011002101 in words is "twenty-one billion, eleven million, two thousand, one hundred one".