645664211 has 8 divisors (see below), whose sum is σ = 676304640. Its totient is φ = 615237832.

The previous prime is 645664189. The next prime is 645664219. The reversal of 645664211 is 112466546.

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 645664211 - 2⁶ = 645664147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645664219) 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, 47321 + ... + 59418.

It is an arithmetic number, because the mean of its divisors is an integer number (84538080).

Almost surely, 2^645664211 is an apocalyptic number.

645664211 is a deficient number, since it is larger than the sum of its proper divisors (30640429).

645664211 is a wasteful number, since it uses less digits than its factorization.

645664211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107025.

The product of its digits is 34560, while the sum is 35.

The square root of 645664211 is about 25409.9234748946. The cubic root of 645664211 is about 864.3087401673.

The spelling of 645664211 in words is "six hundred forty-five million, six hundred sixty-four thousand, two hundred eleven".