1645363440 has 240 divisors, whose sum is σ = 6519392256. Its totient is φ = 363916800.

The previous prime is 1645363403. The next prime is 1645363469. The reversal of 1645363440 is 443635461.

1645363440 is a `hidden beast` number, since 1 + 645 + 3 + 6 + 3 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1645363395 and 1645363404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 150975 + ... + 161505.

Almost surely, 2^1645363440 is an apocalyptic number.

1645363440 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 1645363440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3259696128).

1645363440 is an abundant number, since it is smaller than the sum of its proper divisors (4874028816).

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

1645363440 is a wasteful number, since it uses less digits than its factorization.

1645363440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10588 (or 10579 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 1645363440 is about 40563.0797647319. The cubic root of 1645363440 is about 1180.5578708484.

It can be divided in two parts, 1645 and 363440, that added together give a triangular number (365085 = T₈₅₄).

The spelling of 1645363440 in words is "one billion, six hundred forty-five million, three hundred sixty-three thousand, four hundred forty".