1656684989 has 2 divisors, whose sum is σ = 1656684990. Its totient is φ = 1656684988.

The previous prime is 1656684979. The next prime is 1656685007. The reversal of 1656684989 is 9894866561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1612022500 + 44662489 = 40150^2 + 6683^2 .

It is a cyclic number.

It is not a de Polignac number, because 1656684989 - 2²⁰ = 1655636413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1656684949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828342494 + 828342495.

It is an arithmetic number, because the mean of its divisors is an integer number (828342495).

Almost surely, 2^1656684989 is an apocalyptic number.

It is an amenable number.

1656684989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656684989 is an equidigital number, since it uses as much as digits as its factorization.

1656684989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22394880, while the sum is 62.

The square root of 1656684989 is about 40702.3953717714. The cubic root of 1656684989 is about 1183.2594430531.

The spelling of 1656684989 in words is "one billion, six hundred fifty-six million, six hundred eighty-four thousand, nine hundred eighty-nine".