645611601 has 32 divisors (see below), whose sum is σ = 951471360. Its totient is φ = 387559424.

The previous prime is 645611573. The next prime is 645611627. The reversal of 645611601 is 106116546.

It is a cyclic number.

It is not a de Polignac number, because 645611601 - 2⁵ = 645611569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645611201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 165196 + ... + 169058.

It is an arithmetic number, because the mean of its divisors is an integer number (29733480).

Almost surely, 2^645611601 is an apocalyptic number.

It is an amenable number.

645611601 is a deficient number, since it is larger than the sum of its proper divisors (305859759).

645611601 is a wasteful number, since it uses less digits than its factorization.

645611601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4025.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 645611601 is about 25408.8882283346. Note that the first 3 decimals coincide. The cubic root of 645611601 is about 864.2852643331.

The spelling of 645611601 in words is "six hundred forty-five million, six hundred eleven thousand, six hundred one".