645193871 has 8 divisors (see below), whose sum is σ = 739972224. Its totient is φ = 551067480.

The previous prime is 645193847. The next prime is 645193883. The reversal of 645193871 is 178391546.

645193871 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 645193871 - 2⁶ = 645193807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645193831) 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, 160865 + ... + 164826.

It is an arithmetic number, because the mean of its divisors is an integer number (92496528).

Almost surely, 2^645193871 is an apocalyptic number.

645193871 is a deficient number, since it is larger than the sum of its proper divisors (94778353).

645193871 is a wasteful number, since it uses less digits than its factorization.

645193871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325981.

The product of its digits is 181440, while the sum is 44.

The square root of 645193871 is about 25400.6667432176. Note that the first 3 decimals coincide. The cubic root of 645193871 is about 864.0988179835.

The spelling of 645193871 in words is "six hundred forty-five million, one hundred ninety-three thousand, eight hundred seventy-one".