1645617663 has 24 divisors (see below), whose sum is σ = 2519185968. Its totient is φ = 1031576832.

The previous prime is 1645617647. The next prime is 1645617667. The reversal of 1645617663 is 3667165461.

1645617663 is a `hidden beast` number, since 16 + 4 + 561 + 76 + 6 + 3 = 666.

1645617663 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1645617663 - 2⁴ = 1645617647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645617667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 181156 + ... + 190022.

It is an arithmetic number, because the mean of its divisors is an integer number (104966082).

Almost surely, 2^1645617663 is an apocalyptic number.

1645617663 is a deficient number, since it is larger than the sum of its proper divisors (873568305).

1645617663 is a wasteful number, since it uses less digits than its factorization.

1645617663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10103 (or 10100 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 1645617663 is about 40566.2133184748. The cubic root of 1645617663 is about 1180.6186698793.

The spelling of 1645617663 in words is "one billion, six hundred forty-five million, six hundred seventeen thousand, six hundred sixty-three".