2145645840 has 80 divisors (see below), whose sum is σ = 7163166528. Its totient is φ = 528158208.

The previous prime is 2145645797. The next prime is 2145645841. The reversal of 2145645840 is 485465412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (2145645841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 340734 + ... + 346973.

Almost surely, 2^2145645840 is an apocalyptic number.

2145645840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2145645840 is an abundant number, since it is smaller than the sum of its proper divisors (5017520688).

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

2145645840 is a wasteful number, since it uses less digits than its factorization.

2145645840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 687736 (or 687730 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 39.

The square root of 2145645840 is about 46321.1165668532. The cubic root of 2145645840 is about 1289.7910123558.

The spelling of 2145645840 in words is "two billion, one hundred forty-five million, six hundred forty-five thousand, eight hundred forty".