1980400221 has 12 divisors (see below), whose sum is σ = 2875101372. Its totient is φ = 1313563776.

The previous prime is 1980400207. The next prime is 1980400243. The reversal of 1980400221 is 1220040891.

It can be written as a sum of positive squares in 2 ways, for example, as 1839123225 + 141276996 = 42885^2 + 11886^2 .

It is not a de Polignac number, because 1980400221 - 2⁵ = 1980400189 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1980400421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 556716 + ... + 560261.

It is an arithmetic number, because the mean of its divisors is an integer number (239591781).

Almost surely, 2^1980400221 is an apocalyptic number.

It is an amenable number.

1980400221 is a deficient number, since it is larger than the sum of its proper divisors (894701151).

1980400221 is a wasteful number, since it uses less digits than its factorization.

1980400221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1117180 (or 1117177 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 1980400221 is about 44501.6878443953. The cubic root of 1980400221 is about 1255.7918360729.

The spelling of 1980400221 in words is "one billion, nine hundred eighty million, four hundred thousand, two hundred twenty-one".