661101569 has 2 divisors, whose sum is σ = 661101570. Its totient is φ = 661101568.

The previous prime is 661101547. The next prime is 661101601. The reversal of 661101569 is 965101166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 628153969 + 32947600 = 25063^2 + 5740^2 .

It is a cyclic number.

It is not a de Polignac number, because 661101569 - 2²⁰ = 660052993 is a prime.

It is a super-2 number, since 2×661101569² = 874110569068523522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661101169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330550784 + 330550785.

It is an arithmetic number, because the mean of its divisors is an integer number (330550785).

Almost surely, 2^661101569 is an apocalyptic number.

It is an amenable number.

661101569 is a deficient number, since it is larger than the sum of its proper divisors (1).

661101569 is an equidigital number, since it uses as much as digits as its factorization.

661101569 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 661101569 is about 25711.8954766077. The cubic root of 661101569 is about 871.1428891253.

The spelling of 661101569 in words is "six hundred sixty-one million, one hundred one thousand, five hundred sixty-nine".