1645329840 has 640 divisors, whose sum is σ = 6856704000. Its totient is φ = 322882560.

The previous prime is 1645329793. The next prime is 1645329857. The reversal of 1645329840 is 489235461.

It is a super-2 number, since 2×1645329840² = 5414220564788851200, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 1645329792 and 1645329801.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 20826921 + ... + 20826999.

It is an arithmetic number, because the mean of its divisors is an integer number (10713600).

Almost surely, 2^1645329840 is an apocalyptic number.

1645329840 is a gapful number since it is divisible by the number (10) 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 1645329840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3428352000).

1645329840 is an abundant number, since it is smaller than the sum of its proper divisors (5211374160).

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

1645329840 is a wasteful number, since it uses less digits than its factorization.

1645329840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 1645329840 is about 40562.6655928823. The cubic root of 1645329840 is about 1180.5498347283.

The spelling of 1645329840 in words is "one billion, six hundred forty-five million, three hundred twenty-nine thousand, eight hundred forty".