1638920180 has 24 divisors (see below), whose sum is σ = 3534753768. Its totient is φ = 637849728.

The previous prime is 1638920167. The next prime is 1638920197. The reversal of 1638920180 is 810298361.

It can be written as a sum of positive squares in 4 ways, for example, as 985708816 + 653211364 = 31396^2 + 25558^2 .

It is a super-2 number, since 2×1638920180² = 5372118712822464800, which contains 22 as substring.

It is a congruent number.

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, 1106639 + ... + 1108118.

It is an arithmetic number, because the mean of its divisors is an integer number (147281407).

Almost surely, 2^1638920180 is an apocalyptic number.

1638920180 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1638920180 is an abundant number, since it is smaller than the sum of its proper divisors (1895833588).

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

1638920180 is a wasteful number, since it uses less digits than its factorization.

1638920180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2214803 (or 2214801 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 1638920180 is about 40483.5791401897. The cubic root of 1638920180 is about 1179.0148293521.

The spelling of 1638920180 in words is "one billion, six hundred thirty-eight million, nine hundred twenty thousand, one hundred eighty".