1645994840 has 32 divisors (see below), whose sum is σ = 4232558880. Its totient is φ = 564340992.

The previous prime is 1645994837. The next prime is 1645994881. The reversal of 1645994840 is 484995461.

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, 2938997 + ... + 2939556.

It is an arithmetic number, because the mean of its divisors is an integer number (132267465).

Almost surely, 2^1645994840 is an apocalyptic number.

1645994840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645994840 is an abundant number, since it is smaller than the sum of its proper divisors (2586564040).

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

1645994840 is a wasteful number, since it uses less digits than its factorization.

1645994840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5878571 (or 5878567 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 50.

The square root of 1645994840 is about 40570.8619578140. The cubic root of 1645994840 is about 1180.7088625976.

The spelling of 1645994840 in words is "one billion, six hundred forty-five million, nine hundred ninety-four thousand, eight hundred forty".