1643607545 has 16 divisors (see below), whose sum is σ = 2007789120. Its totient is φ = 1291291584.

The previous prime is 1643607517. The next prime is 1643607547. The reversal of 1643607545 is 5457063461.

It is a cyclic number.

It is not a de Polignac number, because 1643607545 - 2²⁴ = 1626830329 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1643607547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 374534 + ... + 378896.

It is an arithmetic number, because the mean of its divisors is an integer number (125486820).

Almost surely, 2^1643607545 is an apocalyptic number.

It is an amenable number.

1643607545 is a deficient number, since it is larger than the sum of its proper divisors (364181575).

1643607545 is a wasteful number, since it uses less digits than its factorization.

1643607545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5704.

The product of its (nonzero) digits is 302400, while the sum is 41.

The square root of 1643607545 is about 40541.4299821800. The cubic root of 1643607545 is about 1180.1377664009.

The spelling of 1643607545 in words is "one billion, six hundred forty-three million, six hundred seven thousand, five hundred forty-five".