646955139 has 4 divisors (see below), whose sum is σ = 862606856. Its totient is φ = 431303424.

The previous prime is 646955137. The next prime is 646955207. The reversal of 646955139 is 931559646.

It is a happy number.

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

It is not a de Polignac number, because 646955139 - 2¹ = 646955137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646955131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107825854 + ... + 107825859.

It is an arithmetic number, because the mean of its divisors is an integer number (215651714).

Almost surely, 2^646955139 is an apocalyptic number.

646955139 is a deficient number, since it is larger than the sum of its proper divisors (215651717).

646955139 is a wasteful number, since it uses less digits than its factorization.

646955139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215651716.

The product of its digits is 874800, while the sum is 48.

The square root of 646955139 is about 25435.3128347186. The cubic root of 646955139 is about 864.8843838480.

The spelling of 646955139 in words is "six hundred forty-six million, nine hundred fifty-five thousand, one hundred thirty-nine".