387928661 has 16 divisors (see below), whose sum is σ = 419223600. Its totient is φ = 357654528.

The previous prime is 387928633. The next prime is 387928669. The reversal of 387928661 is 166829783.

It can be written as a sum of positive squares in 8 ways, for example, as 135722500 + 252206161 = 11650^2 + 15881^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-387928661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (387928669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 169835 + ... + 172103.

It is an arithmetic number, because the mean of its divisors is an integer number (26201475).

Almost surely, 2^387928661 is an apocalyptic number.

It is an amenable number.

387928661 is a deficient number, since it is larger than the sum of its proper divisors (31294939).

387928661 is a wasteful number, since it uses less digits than its factorization.

387928661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2488.

The product of its digits is 870912, while the sum is 50.

The square root of 387928661 is about 19695.9046758457. The cubic root of 387928661 is about 729.3185991642.

The spelling of 387928661 in words is "three hundred eighty-seven million, nine hundred twenty-eight thousand, six hundred sixty-one".