1645128 has 48 divisors (see below), whose sum is σ = 4531020. Its totient is φ = 539136.

The previous prime is 1645123. The next prime is 1645129. The reversal of 1645128 is 8215461.

1645128 is a `hidden beast` number, since 1 + 645 + 12 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1483524 + 161604 = 1218^2 + 402^2 .

It is a super-2 number, since 2×1645128² = 5412892272768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1645123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5100 + ... + 5412.

2^1645128 is an apocalyptic number.

1645128 is a gapful number since it is divisible by the number (18) 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 1645128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2265510).

1645128 is an abundant number, since it is smaller than the sum of its proper divisors (2885892).

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

1645128 is a wasteful number, since it uses less digits than its factorization.

1645128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 391 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 1645128 is about 1282.6254324627. The cubic root of 1645128 is about 118.0501558304.

The spelling of 1645128 in words is "one million, six hundred forty-five thousand, one hundred twenty-eight".