1565611601 has 2 divisors, whose sum is σ = 1565611602. Its totient is φ = 1565611600.

The previous prime is 1565611591. The next prime is 1565611613. The reversal of 1565611601 is 1061165651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1398685201 + 166926400 = 37399^2 + 12920^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1565611601 is a prime.

It is a super-2 number, since 2×1565611601² = 4902279370371566402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1565611681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 782805800 + 782805801.

It is an arithmetic number, because the mean of its divisors is an integer number (782805801).

Almost surely, 2^1565611601 is an apocalyptic number.

It is an amenable number.

1565611601 is a deficient number, since it is larger than the sum of its proper divisors (1).

1565611601 is an equidigital number, since it uses as much as digits as its factorization.

1565611601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1565611601 is about 39567.8101617969. The cubic root of 1565611601 is about 1161.1669788468.

The spelling of 1565611601 in words is "one billion, five hundred sixty-five million, six hundred eleven thousand, six hundred one".