2102666021 has 4 divisors (see below), whose sum is σ = 2104776012. Its totient is φ = 2100556032.

The previous prime is 2102666011. The next prime is 2102666023. The reversal of 2102666021 is 1206662012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 962860900 + 1139805121 = 31030^2 + 33761^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102666021 - 2¹⁰ = 2102664997 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 (2102666023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1053500 + ... + 1055493.

It is an arithmetic number, because the mean of its divisors is an integer number (526194003).

Almost surely, 2^2102666021 is an apocalyptic number.

It is an amenable number.

2102666021 is a deficient number, since it is larger than the sum of its proper divisors (2109991).

2102666021 is an equidigital number, since it uses as much as digits as its factorization.

2102666021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109990.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 2102666021 is about 45854.8363970476. The cubic root of 2102666021 is about 1281.1208486721.

The spelling of 2102666021 in words is "two billion, one hundred two million, six hundred sixty-six thousand, twenty-one".