2021661379 has 4 divisors (see below), whose sum is σ = 2023357176. Its totient is φ = 2019965584.

The previous prime is 2021661361. The next prime is 2021661413. The reversal of 2021661379 is 9731661202.

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

It is a cyclic number.

It is not a de Polignac number, because 2021661379 - 2⁵ = 2021661347 is a prime.

It is a super-2 number, since 2×2021661379² = 8174229462680363282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2021661359) 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, 846109 + ... + 848494.

It is an arithmetic number, because the mean of its divisors is an integer number (505839294).

Almost surely, 2^2021661379 is an apocalyptic number.

2021661379 is a deficient number, since it is larger than the sum of its proper divisors (1695797).

2021661379 is a wasteful number, since it uses less digits than its factorization.

2021661379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1695796.

The product of its (nonzero) digits is 27216, while the sum is 37.

The square root of 2021661379 is about 44962.8889085210. Note that the first 3 decimals coincide. The cubic root of 2021661379 is about 1264.4533310502.

The spelling of 2021661379 in words is "two billion, twenty-one million, six hundred sixty-one thousand, three hundred seventy-nine".