1645020840 has 64 divisors (see below), whose sum is σ = 4973967360. Its totient is φ = 435214080.

The previous prime is 1645020823. The next prime is 1645020847. The reversal of 1645020840 is 480205461.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1645020798 and 1645020807.

It is not an unprimeable number, because it can be changed into a prime (1645020847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38731 + ... + 69210.

It is an arithmetic number, because the mean of its divisors is an integer number (77718240).

Almost surely, 2^1645020840 is an apocalyptic number.

1645020840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645020840 is an abundant number, since it is smaller than the sum of its proper divisors (3328946520).

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

1645020840 is a wasteful number, since it uses less digits than its factorization.

1645020840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108082 (or 108078 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 1645020840 is about 40558.8564927563. The cubic root of 1645020840 is about 1180.4759259941.

The spelling of 1645020840 in words is "one billion, six hundred forty-five million, twenty thousand, eight hundred forty".