20635021 has 16 divisors (see below), whose sum is σ = 23224320. Its totient is φ = 18173680.

The previous prime is 20635009. The next prime is 20635031. The reversal of 20635021 is 12053602.

It is a happy number.

It is the 1855-th star number.

It is a cyclic number.

It is not a de Polignac number, because 20635021 - 2¹¹ = 20632973 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 20635021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20635031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86220 + ... + 86458.

It is an arithmetic number, because the mean of its divisors is an integer number (1451520).

Almost surely, 2^20635021 is an apocalyptic number.

It is an amenable number.

20635021 is a deficient number, since it is larger than the sum of its proper divisors (2589299).

20635021 is a wasteful number, since it uses less digits than its factorization.

20635021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20635021 is about 4542.5786729566. The cubic root of 20635021 is about 274.2847351750.

Adding to 20635021 its reverse (12053602), we get a palindrome (32688623).

The spelling of 20635021 in words is "twenty million, six hundred thirty-five thousand, twenty-one".