21642035 has 4 divisors (see below), whose sum is σ = 25970448. Its totient is φ = 17313624.

The previous prime is 21642017. The next prime is 21642067. The reversal of 21642035 is 53024612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21642035 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 21642035.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2164199 + ... + 2164208.

It is an arithmetic number, because the mean of its divisors is an integer number (6492612).

Almost surely, 2^21642035 is an apocalyptic number.

21642035 is a deficient number, since it is larger than the sum of its proper divisors (4328413).

21642035 is an equidigital number, since it uses as much as digits as its factorization.

21642035 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4328412.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21642035 is about 4652.1000634122. The cubic root of 21642035 is about 278.6758696077.

Adding to 21642035 its reverse (53024612), we get a palindrome (74666647).

The spelling of 21642035 in words is "twenty-one million, six hundred forty-two thousand, thirty-five".