1645890500 has 24 divisors (see below), whose sum is σ = 3594625944. Its totient is φ = 658356000.

The previous prime is 1645890481. The next prime is 1645890529. The reversal of 1645890500 is 50985461.

It can be written as a sum of positive squares in 4 ways, for example, as 614656 + 1645275844 = 784^2 + 40562^2 .

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

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, 1645391 + ... + 1646390.

It is an arithmetic number, because the mean of its divisors is an integer number (149776081).

Almost surely, 2^1645890500 is an apocalyptic number.

1645890500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645890500 is an abundant number, since it is smaller than the sum of its proper divisors (1948735444).

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

1645890500 is a wasteful number, since it uses less digits than its factorization.

1645890500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3291800 (or 3291788 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 1645890500 is about 40569.5760391947. The cubic root of 1645890500 is about 1180.6839135996.

The spelling of 1645890500 in words is "one billion, six hundred forty-five million, eight hundred ninety thousand, five hundred".