21101005 has 8 divisors (see below), whose sum is σ = 26422272. Its totient is φ = 16146768.

The previous prime is 21100999. The next prime is 21101027. The reversal of 21101005 is 50010112.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101005 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100982 and 21101000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91629 + ... + 91858.

It is an arithmetic number, because the mean of its divisors is an integer number (3302784).

Almost surely, 2^21101005 is an apocalyptic number.

It is an amenable number.

21101005 is a deficient number, since it is larger than the sum of its proper divisors (5321267).

21101005 is a wasteful number, since it uses less digits than its factorization.

21101005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183515.

The product of its (nonzero) digits is 10, while the sum is 10.

The square root of 21101005 is about 4593.5830241762. The cubic root of 21101005 is about 276.3340359801.

Adding to 21101005 its reverse (50010112), we get a palindrome (71111117).

The spelling of 21101005 in words is "twenty-one million, one hundred one thousand, five".