1645165536 has 192 divisors, whose sum is σ = 5138251776. Its totient is φ = 451008000.

The previous prime is 1645165513. The next prime is 1645165537. The reversal of 1645165536 is 6355615461.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645165537) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3145371 + ... + 3145893.

It is an arithmetic number, because the mean of its divisors is an integer number (26761728).

Almost surely, 2^1645165536 is an apocalyptic number.

1645165536 is a gapful number since it is divisible by the number (16) 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 1645165536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2569125888).

1645165536 is an abundant number, since it is smaller than the sum of its proper divisors (3493086240).

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

1645165536 is a wasteful number, since it uses less digits than its factorization.

1645165536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725 (or 717 counting only the distinct ones).

The product of its digits is 324000, while the sum is 42.

The square root of 1645165536 is about 40560.6402316334. The cubic root of 1645165536 is about 1180.5105365256.

The spelling of 1645165536 in words is "one billion, six hundred forty-five million, one hundred sixty-five thousand, five hundred thirty-six".