2021645671 has 8 divisors (see below), whose sum is σ = 2074391424. Its totient is φ = 1969063680.

The previous prime is 2021645617. The next prime is 2021645699. The reversal of 2021645671 is 1765461202.

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 2021645671 - 2⁹ = 2021645159 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 (2021642671) 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, 15730 + ... + 65503.

It is an arithmetic number, because the mean of its divisors is an integer number (259298928).

Almost surely, 2^2021645671 is an apocalyptic number.

2021645671 is a deficient number, since it is larger than the sum of its proper divisors (52745753).

2021645671 is an equidigital number, since it uses as much as digits as its factorization.

2021645671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81881.

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 2021645671 is about 44962.7142307935. The cubic root of 2021645671 is about 1264.4500561720.

The spelling of 2021645671 in words is "two billion, twenty-one million, six hundred forty-five thousand, six hundred seventy-one".