2220746821 has 4 divisors (see below), whose sum is σ = 2227980832. Its totient is φ = 2213512812.

The previous prime is 2220746813. The next prime is 2220746849. The reversal of 2220746821 is 1286470222.

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 an emirpimes, since its reverse is a distinct semiprime: 1286470222 = 2 ⋅643235111.

It is a cyclic number.

It is not a de Polignac number, because 2220746821 - 2³ = 2220746813 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 (2220746861) 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, 3616545 + ... + 3617158.

It is an arithmetic number, because the mean of its divisors is an integer number (556995208).

Almost surely, 2^2220746821 is an apocalyptic number.

It is an amenable number.

2220746821 is a deficient number, since it is larger than the sum of its proper divisors (7234011).

2220746821 is an equidigital number, since it uses as much as digits as its factorization.

2220746821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7234010.

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 2220746821 is about 47124.8004876413. The cubic root of 2220746821 is about 1304.6670164265.

The spelling of 2220746821 in words is "two billion, two hundred twenty million, seven hundred forty-six thousand, eight hundred twenty-one".