1778224561 has 3 divisors (see below), whose sum is σ = 1778266731. Its totient is φ = 1778182392.

The previous prime is 1778224549. The next prime is 1778224589. The reversal of 1778224561 is 1654228771.

The square root of 1778224561 is 42169.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1754018161 + 24206400 = 41881^2 + 4920^2 .

It is not a de Polignac number, because 1778224561 - 2⁵ = 1778224529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1778224501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 21085 + ... + 63253.

It is an arithmetic number, because the mean of its divisors is an integer number (592755577).

Almost surely, 2^1778224561 is an apocalyptic number.

1778224561 is the 42169-th square number.

1778224561 is the 21085-th centered octagonal number.

It is an amenable number.

1778224561 is a deficient number, since it is larger than the sum of its proper divisors (42170).

1778224561 is an frugal number, since it uses more digits than its factorization.

1778224561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84338 (or 42169 counting only the distinct ones).

The product of its digits is 188160, while the sum is 43.

The cubic root of 1778224561 is about 1211.5152024288.

The spelling of 1778224561 in words is "one billion, seven hundred seventy-eight million, two hundred twenty-four thousand, five hundred sixty-one".