645442005 has 32 divisors (see below), whose sum is σ = 1131016320. Its totient is φ = 312364800.

The previous prime is 645441971. The next prime is 645442013. The reversal of 645442005 is 500244546.

It is not a de Polignac number, because 645442005 - 2⁷ = 645441877 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16546 + ... + 39555.

It is an arithmetic number, because the mean of its divisors is an integer number (35344260).

Almost surely, 2^645442005 is an apocalyptic number.

645442005 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

645442005 is a deficient number, since it is larger than the sum of its proper divisors (485574315).

645442005 is a wasteful number, since it uses less digits than its factorization.

645442005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56181.

The product of its (nonzero) digits is 19200, while the sum is 30.

The square root of 645442005 is about 25405.5506730321. The cubic root of 645442005 is about 864.2095778779.

The spelling of 645442005 in words is "six hundred forty-five million, four hundred forty-two thousand, five".