6646891604 has 6 divisors (see below), whose sum is σ = 11632060314. Its totient is φ = 3323445800.

The previous prime is 6646891549. The next prime is 6646891621. The reversal of 6646891604 is 4061986466.

It can be written as a sum of positive squares in only one way, i.e., 3844248004 + 2802643600 = 62002^2 + 52940^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830861447 + ... + 830861454.

It is an arithmetic number, because the mean of its divisors is an integer number (1938676719).

Almost surely, 2^6646891604 is an apocalyptic number.

It is an amenable number.

6646891604 is a deficient number, since it is larger than the sum of its proper divisors (4985168710).

6646891604 is a wasteful number, since it uses less digits than its factorization.

6646891604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661722905 (or 1661722903 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 50.

The square root of 6646891604 is about 81528.4711251229. The cubic root of 6646891604 is about 1880.2093101043.

The spelling of 6646891604 in words is "six billion, six hundred forty-six million, eight hundred ninety-one thousand, six hundred four".