645507305 has 8 divisors (see below), whose sum is σ = 808287552. Its totient is φ = 493953328.

The previous prime is 645507301. The next prime is 645507319. The reversal of 645507305 is 503705546.

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

It is a cyclic number.

It is not a de Polignac number, because 645507305 - 2² = 645507301 is a prime.

It is a super-3 number, since 3×645507305³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645507301) 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, 2806439 + ... + 2806668.

It is an arithmetic number, because the mean of its divisors is an integer number (101035944).

Almost surely, 2^645507305 is an apocalyptic number.

It is an amenable number.

645507305 is a deficient number, since it is larger than the sum of its proper divisors (162780247).

645507305 is a wasteful number, since it uses less digits than its factorization.

645507305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5613135.

The product of its (nonzero) digits is 63000, while the sum is 35.

The square root of 645507305 is about 25406.8357927547. The cubic root of 645507305 is about 864.2387212050.

The spelling of 645507305 in words is "six hundred forty-five million, five hundred seven thousand, three hundred five".