616668021 has 12 divisors (see below), whose sum is σ = 891911020. Its totient is φ = 410572800.

The previous prime is 616668001. The next prime is 616668023. The reversal of 616668021 is 120866616.

616668021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 98604900 + 518063121 = 9930^2 + 22761^2 .

It is not a de Polignac number, because 616668021 - 2⁷ = 616667893 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 (616668023) 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, 37630 + ... + 51471.

Almost surely, 2^616668021 is an apocalyptic number.

It is an amenable number.

616668021 is a deficient number, since it is larger than the sum of its proper divisors (275242999).

616668021 is a wasteful number, since it uses less digits than its factorization.

616668021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89876 (or 89873 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 616668021 is about 24832.8013119745. The cubic root of 616668021 is about 851.1716350328.

The spelling of 616668021 in words is "six hundred sixteen million, six hundred sixty-eight thousand, twenty-one".