1606616621 has 2 divisors, whose sum is σ = 1606616622. Its totient is φ = 1606616620.

The previous prime is 1606616587. The next prime is 1606616681. The reversal of 1606616621 is 1266166061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 827425225 + 779191396 = 28765^2 + 27914^2 .

It is a cyclic number.

It is not a de Polignac number, because 1606616621 - 2¹⁰ = 1606615597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1606616681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 803308310 + 803308311.

It is an arithmetic number, because the mean of its divisors is an integer number (803308311).

Almost surely, 2^1606616621 is an apocalyptic number.

It is an amenable number.

1606616621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1606616621 is an equidigital number, since it uses as much as digits as its factorization.

1606616621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 1606616621 is about 40082.6224316723. The cubic root of 1606616621 is about 1171.2171377013.

The spelling of 1606616621 in words is "one billion, six hundred six million, six hundred sixteen thousand, six hundred twenty-one".