1645051680 has 288 divisors, whose sum is σ = 6026529600. Its totient is φ = 423263232.

The previous prime is 1645051663. The next prime is 1645051687. The reversal of 1645051680 is 861505461.

1645051680 is a `hidden beast` number, since 1 + 64 + 5 + 0 + 516 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645051687) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1126791 + ... + 1128249.

It is an arithmetic number, because the mean of its divisors is an integer number (20925450).

Almost surely, 2^1645051680 is an apocalyptic number.

1645051680 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 1645051680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3013264800).

1645051680 is an abundant number, since it is smaller than the sum of its proper divisors (4381477920).

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

1645051680 is a wasteful number, since it uses less digits than its factorization.

1645051680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1518 (or 1498 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1645051680 is about 40559.2366792079. The cubic root of 1645051680 is about 1180.4833029321.

The spelling of 1645051680 in words is "one billion, six hundred forty-five million, fifty-one thousand, six hundred eighty".