1785640640 has 56 divisors (see below), whose sum is σ = 4859499552. Its totient is φ = 612218880.

The previous prime is 1785640631. The next prime is 1785640643. The reversal of 1785640640 is 460465871.

It is a tau number, because it is divible by the number of its divisors (56).

It is not an unprimeable number, because it can be changed into a prime (1785640643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 396341 + ... + 400820.

Almost surely, 2^1785640640 is an apocalyptic number.

1785640640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1785640640 is an abundant number, since it is smaller than the sum of its proper divisors (3073858912).

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

1785640640 is an equidigital number, since it uses as much as digits as its factorization.

1785640640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 797185 (or 797175 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 41.

The square root of 1785640640 is about 42256.8413395985. The cubic root of 1785640640 is about 1213.1970730799.

The spelling of 1785640640 in words is "one billion, seven hundred eighty-five million, six hundred forty thousand, six hundred forty".