2102020021 has 8 divisors (see below), whose sum is σ = 2227541400. Its totient is φ = 1980034560.

The previous prime is 2102020003. The next prime is 2102020073. The reversal of 2102020021 is 1200202012.

It can be written as a sum of positive squares in 4 ways, for example, as 10329796 + 2091690225 = 3214^2 + 45735^2 .

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 2102020021 - 2²⁷ = 1967802293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2102050021) 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, 882756 + ... + 885133.

It is an arithmetic number, because the mean of its divisors is an integer number (278442675).

Almost surely, 2^2102020021 is an apocalyptic number.

It is an amenable number.

2102020021 is a deficient number, since it is larger than the sum of its proper divisors (125521379).

2102020021 is a wasteful number, since it uses less digits than its factorization.

2102020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1767959.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2102020021 is about 45847.7918879416. The cubic root of 2102020021 is about 1280.9896360704.

Adding to 2102020021 its reverse (1200202012), we get a palindrome (3302222033).

It can be divided in two parts, 21020 and 20021, that added together give a triangular number (41041 = T₂₈₆).

The spelling of 2102020021 in words is "two billion, one hundred two million, twenty thousand, twenty-one".