1645788641 has 8 divisors (see below), whose sum is σ = 1881536064. Its totient is φ = 1410199920.

The previous prime is 1645788631. The next prime is 1645788643. The reversal of 1645788641 is 1468875461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645788641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1645788641.

It is not an unprimeable number, because it can be changed into a prime (1645788643) 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, 16550 + ... + 59711.

It is an arithmetic number, because the mean of its divisors is an integer number (235192008).

Almost surely, 2^1645788641 is an apocalyptic number.

It is an amenable number.

1645788641 is a deficient number, since it is larger than the sum of its proper divisors (235747423).

1645788641 is an equidigital number, since it uses as much as digits as its factorization.

1645788641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79351.

The product of its digits is 1290240, while the sum is 50.

The square root of 1645788641 is about 40568.3206578729. The cubic root of 1645788641 is about 1180.6595568226.

The spelling of 1645788641 in words is "one billion, six hundred forty-five million, seven hundred eighty-eight thousand, six hundred forty-one".