21381035 has 12 divisors (see below), whose sum is σ = 27783792. Its totient is φ = 15788448.

The previous prime is 21380981. The next prime is 21381037. The reversal of 21381035 is 53018312.

It is not a de Polignac number, because 21381035 - 2⁶ = 21380971 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21381035.

It is not an unprimeable number, because it can be changed into a prime (21381037) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11807 + ... + 13496.

It is an arithmetic number, because the mean of its divisors is an integer number (2315316).

Almost surely, 2^21381035 is an apocalyptic number.

21381035 is a deficient number, since it is larger than the sum of its proper divisors (6402757).

21381035 is a wasteful number, since it uses less digits than its factorization.

21381035 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25334 (or 25321 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21381035 is about 4623.9631270156. The cubic root of 21381035 is about 277.5510714107.

Adding to 21381035 its reverse (53018312), we get a palindrome (74399347).

The spelling of 21381035 in words is "twenty-one million, three hundred eighty-one thousand, thirty-five".