616389921 has 12 divisors (see below), whose sum is σ = 1017532672. Its totient is φ = 352222776.

The previous prime is 616389899. The next prime is 616389923. The reversal of 616389921 is 129983616.

It is a happy number.

616389921 is a `hidden beast` number, since 6 + 1 + 638 + 9 + 9 + 2 + 1 = 666.

616389921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 616389921 - 2¹⁸ = 616127777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (616389923) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4891921 + ... + 4892046.

Almost surely, 2^616389921 is an apocalyptic number.

It is an amenable number.

616389921 is a deficient number, since it is larger than the sum of its proper divisors (401142751).

616389921 is a wasteful number, since it uses less digits than its factorization.

616389921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9783980 (or 9783977 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 616389921 is about 24827.2012317136. The cubic root of 616389921 is about 851.0436642739.

The spelling of 616389921 in words is "six hundred sixteen million, three hundred eighty-nine thousand, nine hundred twenty-one".