2021966509 has 4 divisors (see below), whose sum is σ = 2022057216. Its totient is φ = 2021875804.

The previous prime is 2021966497. The next prime is 2021966539. The reversal of 2021966509 is 9056691202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2021966509 - 2⁵ = 2021966477 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2021966539) 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, 13812 + ... + 65074.

It is an arithmetic number, because the mean of its divisors is an integer number (505514304).

Almost surely, 2^2021966509 is an apocalyptic number.

It is an amenable number.

2021966509 is a deficient number, since it is larger than the sum of its proper divisors (90707).

2021966509 is an equidigital number, since it uses as much as digits as its factorization.

2021966509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90706.

The product of its (nonzero) digits is 58320, while the sum is 40.

The square root of 2021966509 is about 44966.2819121172. The cubic root of 2021966509 is about 1264.5169426322.

The spelling of 2021966509 in words is "two billion, twenty-one million, nine hundred sixty-six thousand, five hundred nine".