1800642640 has 40 divisors (see below), whose sum is σ = 4204505448. Its totient is φ = 717158400.

The previous prime is 1800642631. The next prime is 1800642643. The reversal of 1800642640 is 462460081.

It can be written as a sum of positive squares in 4 ways, for example, as 37650496 + 1762992144 = 6136^2 + 41988^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800642643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29661 + ... + 66940.

Almost surely, 2^1800642640 is an apocalyptic number.

1800642640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1800642640 is an abundant number, since it is smaller than the sum of its proper divisors (2403862808).

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

1800642640 is a wasteful number, since it uses less digits than its factorization.

1800642640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96847 (or 96841 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 1800642640 is about 42433.9797803600. The cubic root of 1800642640 is about 1216.5851473081.

The spelling of 1800642640 in words is "one billion, eight hundred million, six hundred forty-two thousand, six hundred forty".