2221720385 has 4 divisors (see below), whose sum is σ = 2666064468. Its totient is φ = 1777376304.

The previous prime is 2221720379. The next prime is 2221720393. The reversal of 2221720385 is 5830271222.

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 868657729 + 1353062656 = 29473^2 + 36784^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221720385 - 2¹⁰ = 2221719361 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222172034 + ... + 222172043.

It is an arithmetic number, because the mean of its divisors is an integer number (666516117).

Almost surely, 2^2221720385 is an apocalyptic number.

It is an amenable number.

2221720385 is a deficient number, since it is larger than the sum of its proper divisors (444344083).

2221720385 is an equidigital number, since it uses as much as digits as its factorization.

2221720385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444344082.

The product of its (nonzero) digits is 13440, while the sum is 32.

The square root of 2221720385 is about 47135.1289910190. The cubic root of 2221720385 is about 1304.8576416792.

The spelling of 2221720385 in words is "two billion, two hundred twenty-one million, seven hundred twenty thousand, three hundred eighty-five".