646404744049 has 9 divisors (see below), whose sum is σ = 657594708537. Its totient is φ = 635402099844.

The previous prime is 646404744043. The next prime is 646404744091. The reversal of 646404744049 is 940447404646.

The square root of 646404744049 is 803993.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 646404744049 - 2³⁷ = 508965790577 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 646404743987 and 646404744005.

It is not an unprimeable number, because it can be changed into a prime (646404744043) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 47428774 + ... + 47442400.

Almost surely, 2^646404744049 is an apocalyptic number.

646404744049 is the 803993-rd square number.

646404744049 is the 401997-th centered octagonal number.

It is an amenable number.

646404744049 is a deficient number, since it is larger than the sum of its proper divisors (11189964488).

646404744049 is an frugal number, since it uses more digits than its factorization.

646404744049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27372 (or 13686 counting only the distinct ones).

The product of its (nonzero) digits is 9289728, while the sum is 52.

The spelling of 646404744049 in words is "six hundred forty-six billion, four hundred four million, seven hundred forty-four thousand, forty-nine".