1644650651 has 12 divisors (see below), whose sum is σ = 1918604952. Its totient is φ = 1405692288.

The previous prime is 1644650647. The next prime is 1644650699. The reversal of 1644650651 is 1560564461.

It is a happy number.

It is not a de Polignac number, because 1644650651 - 2² = 1644650647 is a prime.

It is a super-3 number, since 3×1644650651³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1644650551) 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 11 ways as a sum of consecutive naturals, for example, 30245 + ... + 64838.

It is an arithmetic number, because the mean of its divisors is an integer number (159883746).

Almost surely, 2^1644650651 is an apocalyptic number.

1644650651 is a deficient number, since it is larger than the sum of its proper divisors (273954301).

1644650651 is an equidigital number, since it uses as much as digits as its factorization.

1644650651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95450 (or 95443 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 1644650651 is about 40554.2926334562. The cubic root of 1644650651 is about 1180.3873694692.

The spelling of 1644650651 in words is "one billion, six hundred forty-four million, six hundred fifty thousand, six hundred fifty-one".