2105020021 has 16 divisors (see below), whose sum is σ = 2356308864. Its totient is φ = 1867765824.

The previous prime is 2105019997. The next prime is 2105020037. The reversal of 2105020021 is 1200205012.

It is a cyclic number.

It is not a de Polignac number, because 2105020021 - 2¹⁹ = 2104495733 is a prime.

It is a super-2 number, since 2×2105020021² = 8862218577621680882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a junction number, because it is equal to n+sod(n) for n = 2105019983 and 2105020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2105020081) 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, 13560 + ... + 66286.

It is an arithmetic number, because the mean of its divisors is an integer number (147269304).

Almost surely, 2^2105020021 is an apocalyptic number.

It is an amenable number.

2105020021 is a deficient number, since it is larger than the sum of its proper divisors (251288843).

2105020021 is a wasteful number, since it uses less digits than its factorization.

2105020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52860.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 2105020021 is about 45880.4971747256. The cubic root of 2105020021 is about 1281.5987552497.

Adding to 2105020021 its reverse (1200205012), we get a palindrome (3305225033).

The spelling of 2105020021 in words is "two billion, one hundred five million, twenty thousand, twenty-one".