1606538561 has 2 divisors, whose sum is σ = 1606538562. Its totient is φ = 1606538560.

The previous prime is 1606538519. The next prime is 1606538567. The reversal of 1606538561 is 1658356061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1199306161 + 407232400 = 34631^2 + 20180^2 .

It is a cyclic number.

It is not a de Polignac number, because 1606538561 - 2¹⁸ = 1606276417 is a prime.

It is a super-2 number, since 2×1606538561² = 5161932295959901442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1606538567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 803269280 + 803269281.

It is an arithmetic number, because the mean of its divisors is an integer number (803269281).

Almost surely, 2^1606538561 is an apocalyptic number.

It is an amenable number.

1606538561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1606538561 is an equidigital number, since it uses as much as digits as its factorization.

1606538561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129600, while the sum is 41.

The square root of 1606538561 is about 40081.6486811608. The cubic root of 1606538561 is about 1171.1981689174.

The spelling of 1606538561 in words is "one billion, six hundred six million, five hundred thirty-eight thousand, five hundred sixty-one".