1605956897 has 2 divisors, whose sum is σ = 1605956898. Its totient is φ = 1605956896.

The previous prime is 1605956887. The next prime is 1605956977. The reversal of 1605956897 is 7986595061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1313410081 + 292546816 = 36241^2 + 17104^2 .

It is an emirp because it is prime and its reverse (7986595061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1605956897 - 2²⁶ = 1538848033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1605956837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802978448 + 802978449.

It is an arithmetic number, because the mean of its divisors is an integer number (802978449).

Almost surely, 2^1605956897 is an apocalyptic number.

It is an amenable number.

1605956897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605956897 is an equidigital number, since it uses as much as digits as its factorization.

1605956897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4082400, while the sum is 56.

The square root of 1605956897 is about 40074.3920353135. The cubic root of 1605956897 is about 1171.0568036945.

The spelling of 1605956897 in words is "one billion, six hundred five million, nine hundred fifty-six thousand, eight hundred ninety-seven".