646631911 has 4 divisors (see below), whose sum is σ = 646759152. Its totient is φ = 646504672.

The previous prime is 646631899. The next prime is 646631929. The reversal of 646631911 is 119136646.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646631911 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 (646631971) 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, 55666 + ... + 66271.

It is an arithmetic number, because the mean of its divisors is an integer number (161689788).

Almost surely, 2^646631911 is an apocalyptic number.

646631911 is a deficient number, since it is larger than the sum of its proper divisors (127241).

646631911 is a wasteful number, since it uses less digits than its factorization.

646631911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127240.

The product of its digits is 23328, while the sum is 37.

The square root of 646631911 is about 25428.9581186489. The cubic root of 646631911 is about 864.7403236691.

The spelling of 646631911 in words is "six hundred forty-six million, six hundred thirty-one thousand, nine hundred eleven".