1980209540 has 24 divisors (see below), whose sum is σ = 4196595480. Its totient is φ = 784816128.

The previous prime is 1980209533. The next prime is 1980209551. The reversal of 1980209540 is 459020891.

It can be written as a sum of positive squares in 4 ways, for example, as 1025152324 + 955057216 = 32018^2 + 30904^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1980209494 and 1980209503.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 451997 + ... + 456356.

It is an arithmetic number, because the mean of its divisors is an integer number (174858145).

Almost surely, 2^1980209540 is an apocalyptic number.

1980209540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1980209540 is an abundant number, since it is smaller than the sum of its proper divisors (2216385940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1980209540 is a wasteful number, since it uses less digits than its factorization.

1980209540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908471 (or 908469 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 1980209540 is about 44499.5453909363. The cubic root of 1980209540 is about 1255.7515305282.

The spelling of 1980209540 in words is "one billion, nine hundred eighty million, two hundred nine thousand, five hundred forty".