1645383720 has 32 divisors (see below), whose sum is σ = 4936151520. Its totient is φ = 438768960.

The previous prime is 1645383671. The next prime is 1645383739. The reversal of 1645383720 is 273835461.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6855646 + ... + 6855885.

It is an arithmetic number, because the mean of its divisors is an integer number (154254735).

Almost surely, 2^1645383720 is an apocalyptic number.

1645383720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645383720 is an abundant number, since it is smaller than the sum of its proper divisors (3290767800).

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

1645383720 is a wasteful number, since it uses less digits than its factorization.

1645383720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13711545 (or 13711541 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

The square root of 1645383720 is about 40563.3297449803. The cubic root of 1645383720 is about 1180.5627211679.

The spelling of 1645383720 in words is "one billion, six hundred forty-five million, three hundred eighty-three thousand, seven hundred twenty".