646720323906049 has 4 divisors (see below), whose sum is σ = 647856914985540. Its totient is φ = 645583732826560.

The previous prime is 646720323906047. The next prime is 646720323906091. The reversal of 646720323906049 is 940609323027646.

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

It can be written as a sum of positive squares in 2 ways, for example, as 93202477064449 + 553517846841600 = 9654143^2 + 23526960^2 .

It is a cyclic number.

It is not a de Polignac number, because 646720323906049 - 2¹ = 646720323906047 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646720323906047) 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, 568295538892 + ... + 568295540029.

It is an arithmetic number, because the mean of its divisors is an integer number (161964228746385).

Almost surely, 2^{646720323906049} is an apocalyptic number.

It is an amenable number.

646720323906049 is a deficient number, since it is larger than the sum of its proper divisors (1136591079491).

646720323906049 is a wasteful number, since it uses less digits than its factorization.

646720323906049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1136591079490.

The product of its (nonzero) digits is 70543872, while the sum is 61.

The spelling of 646720323906049 in words is "six hundred forty-six trillion, seven hundred twenty billion, three hundred twenty-three million, nine hundred six thousand, forty-nine".