645891052209 has 32 divisors (see below), whose sum is σ = 940294320000. Its totient is φ = 391961369088.

The previous prime is 645891052187. The next prime is 645891052277. The reversal of 645891052209 is 902250198546.

It is not a de Polignac number, because 645891052209 - 2¹⁹ = 645890527921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645891052109) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21334527 + ... + 21364779.

It is an arithmetic number, because the mean of its divisors is an integer number (29384197500).

Almost surely, 2^645891052209 is an apocalyptic number.

It is an amenable number.

645891052209 is a deficient number, since it is larger than the sum of its proper divisors (294403267791).

645891052209 is a wasteful number, since it uses less digits than its factorization.

645891052209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37841.

The product of its (nonzero) digits is 1555200, while the sum is 51.

The spelling of 645891052209 in words is "six hundred forty-five billion, eight hundred ninety-one million, fifty-two thousand, two hundred nine".