645649319 has 16 divisors (see below), whose sum is σ = 750393600. Its totient is φ = 544065984.

The previous prime is 645649313. The next prime is 645649337. The reversal of 645649319 is 913946546.

It is a happy number.

It is not a de Polignac number, because 645649319 - 2¹² = 645645223 is a prime.

It is a super-2 number, since 2×645649319² = 833726086250327522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645649313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308027 + ... + 310115.

It is an arithmetic number, because the mean of its divisors is an integer number (46899600).

Almost surely, 2^645649319 is an apocalyptic number.

645649319 is a deficient number, since it is larger than the sum of its proper divisors (104744281).

645649319 is a wasteful number, since it uses less digits than its factorization.

645649319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2822.

The product of its digits is 699840, while the sum is 47.

The square root of 645649319 is about 25409.6304380839. The cubic root of 645649319 is about 864.3020951319.

The spelling of 645649319 in words is "six hundred forty-five million, six hundred forty-nine thousand, three hundred nineteen".