646903221959 has 4 divisors (see below), whose sum is σ = 646905208104. Its totient is φ = 646901235816.

The previous prime is 646903221947. The next prime is 646903221977. The reversal of 646903221959 is 959122309646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 959122309646 = 2 ⋅479561154823.

It is a cyclic number.

It is not a de Polignac number, because 646903221959 - 2²⁰ = 646902173383 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 (646903221929) 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, 377192 + ... + 1198365.

It is an arithmetic number, because the mean of its divisors is an integer number (161726302026).

Almost surely, 2^646903221959 is an apocalyptic number.

646903221959 is a deficient number, since it is larger than the sum of its proper divisors (1986145).

646903221959 is a wasteful number, since it uses less digits than its factorization.

646903221959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1986144.

The product of its (nonzero) digits is 6298560, while the sum is 56.

The spelling of 646903221959 in words is "six hundred forty-six billion, nine hundred three million, two hundred twenty-one thousand, nine hundred fifty-nine".