1645549812 has 72 divisors (see below), whose sum is σ = 4480519680. Its totient is φ = 507735360.

The previous prime is 1645549699. The next prime is 1645549837. The reversal of 1645549812 is 2189455461.

1645549812 is a `hidden beast` number, since 1 + 6 + 4 + 554 + 98 + 1 + 2 = 666.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 6387 + ... + 57722.

It is an arithmetic number, because the mean of its divisors is an integer number (62229440).

Almost surely, 2^1645549812 is an apocalyptic number.

1645549812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1645549812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2240259840).

1645549812 is an abundant number, since it is smaller than the sum of its proper divisors (2834969868).

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

1645549812 is a wasteful number, since it uses less digits than its factorization.

1645549812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64173 (or 64168 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The square root of 1645549812 is about 40565.3770104507. The cubic root of 1645549812 is about 1180.6024434981.

The spelling of 1645549812 in words is "one billion, six hundred forty-five million, five hundred forty-nine thousand, eight hundred twelve".