1799981221 has 8 divisors (see below), whose sum is σ = 1869144984. Its totient is φ = 1732020480.

The previous prime is 1799981191. The next prime is 1799981299. The reversal of 1799981221 is 1221899971.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 248409121 + 1551572100 = 15761^2 + 39390^2 .

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 1799981221 - 2¹³ = 1799973029 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 (1799981021) 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, 297706 + ... + 303691.

It is an arithmetic number, because the mean of its divisors is an integer number (233643123).

Almost surely, 2^1799981221 is an apocalyptic number.

It is an amenable number.

1799981221 is a deficient number, since it is larger than the sum of its proper divisors (69163763).

1799981221 is an equidigital number, since it uses as much as digits as its factorization.

1799981221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601511.

The product of its digits is 163296, while the sum is 49.

The square root of 1799981221 is about 42426.1855579782. The cubic root of 1799981221 is about 1216.4361688158.

The spelling of 1799981221 in words is "one billion, seven hundred ninety-nine million, nine hundred eighty-one thousand, two hundred twenty-one".