6405920649 has 6 divisors (see below), whose sum is σ = 9252996506. Its totient is φ = 4270613760.

The previous prime is 6405920629. The next prime is 6405920659. The reversal of 6405920649 is 9460295046.

It can be written as a sum of positive squares in only one way, i.e., 4286975625 + 2118945024 = 65475^2 + 46032^2 .

It is not a de Polignac number, because 6405920649 - 2⁹ = 6405920137 is a prime.

It is a super-2 number, since 2×6405920649² = 82071638722569162402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6405920629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 355884472 + ... + 355884489.

Almost surely, 2^6405920649 is an apocalyptic number.

It is an amenable number.

6405920649 is a deficient number, since it is larger than the sum of its proper divisors (2847075857).

6405920649 is a wasteful number, since it uses less digits than its factorization.

6405920649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711768967 (or 711768964 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The square root of 6405920649 is about 80036.9955020802. The cubic root of 6405920649 is about 1857.2078823687.

The spelling of 6405920649 in words is "six billion, four hundred five million, nine hundred twenty thousand, six hundred forty-nine".