21001101 has 16 divisors (see below), whose sum is σ = 30793728. Its totient is φ = 12625200.

The previous prime is 21001087. The next prime is 21001117. The reversal of 21001101 is 10110012.

It is not a de Polignac number, because 21001101 - 2⁶ = 21001037 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21001101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1686 + ... + 6696.

It is an arithmetic number, because the mean of its divisors is an integer number (1924608).

Almost surely, 2^21001101 is an apocalyptic number.

It is an amenable number.

21001101 is a deficient number, since it is larger than the sum of its proper divisors (9792627).

21001101 is a wasteful number, since it uses less digits than its factorization.

21001101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5152.

The product of its (nonzero) digits is 2, while the sum is 6.

The square root of 21001101 is about 4582.6958223299. The cubic root of 21001101 is about 275.8972391023.

Adding to 21001101 its reverse (10110012), we get a palindrome (31111113).

Multiplying 21001101 by its reverse (10110012), we get a palindrome (212321383123212).

The spelling of 21001101 in words is "twenty-one million, one thousand, one hundred one".