645966199 has 4 divisors (see below), whose sum is σ = 679964440. Its totient is φ = 611967960.

The previous prime is 645966197. The next prime is 645966203. The reversal of 645966199 is 991669546.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645966199 - 2¹ = 645966197 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 (645966197) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16999092 + ... + 16999129.

It is an arithmetic number, because the mean of its divisors is an integer number (169991110).

Almost surely, 2^645966199 is an apocalyptic number.

645966199 is a deficient number, since it is larger than the sum of its proper divisors (33998241).

645966199 is a wasteful number, since it uses less digits than its factorization.

645966199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33998240.

The product of its digits is 3149280, while the sum is 55.

The square root of 645966199 is about 25415.8651043005. The cubic root of 645966199 is about 864.4434697377.

The spelling of 645966199 in words is "six hundred forty-five million, nine hundred sixty-six thousand, one hundred ninety-nine".