20105021 has 8 divisors (see below), whose sum is σ = 21206400. Its totient is φ = 19008000.

The previous prime is 20105009. The next prime is 20105039. The reversal of 20105021 is 12050102.

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

It is a cyclic number.

It is not a de Polignac number, because 20105021 - 2¹⁸ = 19842877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20104993 and 20105011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20105221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13565 + ... + 14973.

It is an arithmetic number, because the mean of its divisors is an integer number (2650800).

Almost surely, 2^20105021 is an apocalyptic number.

It is an amenable number.

20105021 is a deficient number, since it is larger than the sum of its proper divisors (1101379).

20105021 is a wasteful number, since it uses less digits than its factorization.

20105021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 20105021 is about 4483.8622860208. The cubic root of 20105021 is about 271.9160505417.

Adding to 20105021 its reverse (12050102), we get a palindrome (32155123).

The spelling of 20105021 in words is "twenty million, one hundred five thousand, twenty-one".